Transition metal fluorides(TMFs)cathode materials have shown extraordinary promises for electrochemical energy storage,but the understanding of their electrochemical reaction mechanisms is still a matter of debate due...Transition metal fluorides(TMFs)cathode materials have shown extraordinary promises for electrochemical energy storage,but the understanding of their electrochemical reaction mechanisms is still a matter of debate due to the complicated and continuous changing in the battery internal environment.Here,we design a novel iron fluoride(FeF_(2))aggregate assembled with cylindrical nanoparticles as cathode material to build FeF_(2) lithium-ion batteries(LIBs)and employ advanced in situ magnetometry to detect their intrinsic electronic structure during cycling in real time.The results show that FeF_(2) cannot be involved in complete conversion reactions when the FeF_(2) LIBs operate between the conventional voltage range of 1.0–4.0 V,and that the corresponding conversion ratio of FeF_(2) can be further estimated.Importantly,we first demonstrate that the spin-polarized surface capacitance exists in the FeF_(2) cathode by monitoring the magnetic responses over various voltage ranges.The research presents an original and insightful method to examine the conversion mechanism of TMFs and significantly provides an important reference for the future artificial design of energy systems based on spinpolarized surface capacitance.展开更多
Lithium-ion capacitors(LICs)are regarded as a good choice for next-generation energy storage devices,which are expected to exhibit high energy densities,high power densities,and ultra-long cycling stability.Neverthele...Lithium-ion capacitors(LICs)are regarded as a good choice for next-generation energy storage devices,which are expected to exhibit high energy densities,high power densities,and ultra-long cycling stability.Nevertheless,only a few battery-type cathode materials with limited kinetic properties can be employed in LICs,and their electrochemical properties need to be optimized urgently.Here,we exploit a new dendrite-structured FeF_(2) consisting of closely linked primary nanoparticles using a facile solvothermal method combined with the subsequent annealing treatment.This particular architecture has favorable transport pathways for both lithium ions and electrons and exhibits an ultrafast chargedischarge capability with high reversible capacities.Furthermore,a well-designed LIC employing the prepared dendrite-structured FeF_(2) as the battery-type cathode and commercialized activated carbon(AC)as supercapacitor-type anode was constructed in an organic electrolyte containing Li ions.The LIC operates at an optimal voltage range of 1.1-3.8 V and shows a maximum high energy density of 152 W h kg^(-1) and a high power density of 4900 W kg^(-1) based on the total mass of cathode and anode.Long-term cycling stability(85%capacity retention after 2000 cycles)was achieved at 1 A g^(-1).This work suggests that the dendrite-structured FeF_(2) is a prime candidate for high-performance LICs and accelerates the development of hybrid ion capacitor devices.展开更多
Fluoride ferrous(FeF_(2))is viewed as a promising conversion cathode material for next-generation lithiumion batteries(LIBs)due to its high theoretical specific capacity and low cost.Unfortunately,issues such as poor ...Fluoride ferrous(FeF_(2))is viewed as a promising conversion cathode material for next-generation lithiumion batteries(LIBs)due to its high theoretical specific capacity and low cost.Unfortunately,issues such as poor intrinsic conductivity,iron dissolution,and phase separation hinder the application of FeF_(2)in highenergy cathodes.Here,a pressure-induced morphology control method is designed to prepare coralloidlike FeF_(2)nanocrystals with nitrogen-rich carbon coating(c-FeF_(2)@NC).The coralloid-like interconnected crystal structure of c-FeF_(2)@NC contributes to reducing interfacial resistance and enhancing the topotactic transformation during the conversion reaction,and the nitrogen-rich carbon(NC)coating can enhance interfacial stability and kinetic performance.When used as a conversion cathode for LIBs,c-FeF_(2)@NC exhibits a high initial reversible capacity of 503.57 mA h g^(-1)and excellent cycling stability of497.61 m A h g^(-1)with a low capacity decay of 1.19%over 50 cycles at 0.1 A/g.Even at 1 A/g,a stable capacity of 263.78 mA h g^(-1)can still be retained after 200 cycles.The capability of c-FeF_(2)@NC as a conversion cathode for sodium-ion batteries(SIBs)was also evaluated to expand its field of application.Furthermore,two kinds of full batteries have been assembled by employing c-FeF_(2)@NC as cathodes and quantitative limited-Li(LLi)and pre-lithiated reduced graphene oxide(PGO)as anodes,respectively,to envisage the feasibility of practical applications of conversion materials.展开更多
Na_(3)V_(2)(PO_(4))_(3)(NVP)has garnered great attentions as a prospective cathode material for sodium-ion batteries(SIBs)by virtue of its decent theoretical capacity,superior ion conductivity and high structural stab...Na_(3)V_(2)(PO_(4))_(3)(NVP)has garnered great attentions as a prospective cathode material for sodium-ion batteries(SIBs)by virtue of its decent theoretical capacity,superior ion conductivity and high structural stability.However,the inherently poor electronic conductivity and sluggish sodium-ion diffusion kinetics of NVP material give rise to inferior rate performance and unsatisfactory energy density,which strictly confine its further application in SIBs.Thus,it is of significance to boost the sodium storage performance of NVP cathode material.Up to now,many methods have been developed to optimize the electrochemical performance of NVP cathode material.In this review,the latest advances in optimization strategies for improving the electrochemical performance of NVP cathode material are well summarized and discussed,including carbon coating or modification,foreign-ion doping or substitution and nanostructure and morphology design.The foreign-ion doping or substitution is highlighted,involving Na,V,and PO_(4)^(3−)sites,which include single-site doping,multiple-site doping,single-ion doping,multiple-ion doping and so on.Furthermore,the challenges and prospects of high-performance NVP cathode material are also put forward.It is believed that this review can provide a useful reference for designing and developing high-performance NVP cathode material toward the large-scale application in SIBs.展开更多
Lithium nickel oxide(Li_(2)NiO_(2)),as a sacrificial cathode prelithiation additive,has been used to compensate for the lithium loss for improving the lifespan of lithium-ion batteries(LIBs).However,high-cost Li_(2)Ni...Lithium nickel oxide(Li_(2)NiO_(2)),as a sacrificial cathode prelithiation additive,has been used to compensate for the lithium loss for improving the lifespan of lithium-ion batteries(LIBs).However,high-cost Li_(2)NiO_(2)suffers from inferior delithiation kinetics during the first cycle.Herein,we investigated the effects of the cost-effective copper substituted Li_(2)Ni_(1-x)Cu_(x)O_(2)(x=0,0.2,0.3,0.5,0.7)synthesized by a high-temperature solid-phase method on the structure,morphology,electrochemical performance of graphite‖LiFePO_(4)battery.The X-ray diffraction(XRD)refinement result demonstrated that Cu substitution strategy could be favorable for eliminating the NiO_(x)impurity phase and weakening Li-O bond.Analysis on density of states(DOS)indicates that Cu substitution is good for enhancing the electronic conductivity,as well as reducing the delithi-ation voltage polarization confirmed by electrochemical characterizations.Therefore,the optimal Li_(2)Ni_(0.7)Cu_(0.3)O_(2)delivered a high delithiation capacity of 437 mAh·g^(-1),around 8%above that of the pristine Li_(2)NiO_(2).Furthermore,a graphite‖LiFePO_(4)pouch cell with a nominal capacity of 3000 mAh demonstrated a notably improved reversible capacity,energy density and cycle life through introducing 2 wt%Li_(2)Ni_(0.7)Cu_(0.3)O_(2)additive,delivering a 6.2 mAh·g^(-1)higher initial discharge capacity and achieving around 5%improvement in capacity retentnion at 0.5P over 1000 cycles.Additionally,the post-mortem analyses testified that the Li_(2)Ni_(0.7)Cu_(0.3)O_(2)additive could suppress solid electrolyte interphase(SEI)decomposition and homogenize the Li distribution,which benefits to stabilizing interface between graphite and electrolyte,and alleviating dendritic Li plating.In conclusion,the Li_(2)Ni_(0.7)Cu_(0.3)O_(2)additive may offer advantages such as lower cost,lower delithiation voltage and higher prelithiation capacity compared with Li_(2)NiO_(2),making it a promising candidate of cathode prelithiation additive for next-generation LIBs.展开更多
Mn-based P2-type oxides are considered as promising cathodes for Na-ion batteries;however,they face significant challenges,including structural degradation when charged at high cutoff voltages and structural changes u...Mn-based P2-type oxides are considered as promising cathodes for Na-ion batteries;however,they face significant challenges,including structural degradation when charged at high cutoff voltages and structural changes upon storing in a humid atmosphere.In response to these issues,we have designed an oxide with co-doping of Cu and Al which can balance both cost and structural stability.The redox reaction of Cu^(2+/3+)can provide certain charge compensation,and the introduction of Al can further suppress the Jahn-Teller effect of Mn,thereby achieving superior long-term cycling performance.The ex-situ XRD testing indicates that Cu/Al co-doping can effectively suppress the phase transition of P2-O2 at high voltage,thereby explaining the improvement in electrochemical performance.DFT calculations reveal a high chemical tolerance to moisture,with lower adsorption energy for H_(2)O compared to pure Na_(0.67)Cu_(0.25)Mn_(0.75)O_(2).A representative Na_(0.67)Cu_(0.20)Al_(0.05)Mn_(0.75)O_(2)cathode demonstrates impressive reversible capacities of 148.7 mAh/g at 0.2 C,along with a remarkable capacity retention of 79.1%(2 C,500 cycles).展开更多
The electrochemical performance of layered O3-type NaCrO_(2)cathode material is significantly affected by the side reactions between NaCrO_(2)and electrolyte during sodium storage.A uniform Cr_(2)O_(3)coating layer wa...The electrochemical performance of layered O3-type NaCrO_(2)cathode material is significantly affected by the side reactions between NaCrO_(2)and electrolyte during sodium storage.A uniform Cr_(2)O_(3)coating layer was in situ constructed on the surface of NaCrO_(2)by controlling the excess ratio of sodium source.The structure,morphology,valence and electrochemical performance of the Cr_(2)O_(3)-coated NaCrO_(2)were characterized.The results indicate that the Cr_(2)O_(3)coating layer does not alter the crystal structure and morphology of NaCrO_(2),but effectively suppresses the side reactions between NaCrO_(2)and electrolyte,and improves the surface/interfacial stability of NaCrO_(2)material.The Cr_(2)O_(3)-coated NaCrO_(2)exhibits improved electrochemical performance with a capacity retention of 66.4%after 500 cycles at 10C.展开更多
LiMn_(2)O_(4)(LMO) represents one of the most prevalent cathode materials utilized in lithium-ion batteries(LIBs), yet its broader application is often hampered by its limited achievable capacity and significant capac...LiMn_(2)O_(4)(LMO) represents one of the most prevalent cathode materials utilized in lithium-ion batteries(LIBs), yet its broader application is often hampered by its limited achievable capacity and significant capacity degradation during cycling. In this work, a novel dual-doping strategy involving Al^(3+) and Zr^(4+) ions has been employed to refine the atomic structure of LMO's spinel framework. The resultant dual-doped material, Li_(1.06)Mn_(1.97)Zr_(0.01)Al_(0.02)O_(4), exhibits enhanced electrochemical properties, boasting a discharge capacity of 124.9 m Ah/g at a rate of 0.1 C. Furthermore, the formation of stronger Al–O and Zr–O bonds contributes to the stabilization of the delithiated LMO structure. Impressively, 97.7%of its initial capacity is retained after 100 cycles at a 5 C rate. Additionally, enhancements in rate performance and hightemperature cycling stability have also been observed. This study underscores the potential of Al^(3+) and Zr^(4+) dual-doping as a promising approach to enhance LMO cathodes, providing a scalable and efficient means of improving the performance of lithium manganese oxide cathode materials through the incorporation of multiple ions.展开更多
Extending the charging voltage of LiCoO_(2)(LCO)is an ongoing and promising approach to increase its energy density.However,the main challenge of the approach lies in the insuperable cathodic interfacial processes at ...Extending the charging voltage of LiCoO_(2)(LCO)is an ongoing and promising approach to increase its energy density.However,the main challenge of the approach lies in the insuperable cathodic interfacial processes at high voltage,which leads to rapid failure both in the performance and structure of the LCO cathode.Herein,a Li_(2)CO_(3)-based additive was prepared by a simple sand-milling method,enabling a low electrochemical decomposition voltage<4.6 V from commonly>4.8 V,stabilizing the interface of the LCO cathode at 4.6 V.The decomposition of Li_(2)CO_(3)provides extra Li^(+)and CO_(2)to supplement the Li consumption required in the initial irreversible interfacial reactions and rapidly form a uniform and stable cathode electrolyte interphase layer(less organic and more inorganic components)on the LCO cathode by reducing CO_(2).Thus,the phase transformation and the emergence of high-valent Co ions on the surface of LCO at 4.6 V high voltage were inhibited.Thanks to this,with 2%Li_(2)CO_(3)-based additive,the capacity retention of commercial LCO at a high voltage of 4.6 V at 0.5 C for 100 cycles was improved from 59.3%to 79.3%.This work improves the high-voltage stability of LCO and provides a new idea for realizing the high-voltage operation of batteries.展开更多
As a cathode material for thermal batteries,NiS_(2)has a high theoretical capacity but low thermal stability.Besides,the poor formability of NiS_(2)powders also restricts the cathode performance of thermal batteries.I...As a cathode material for thermal batteries,NiS_(2)has a high theoretical capacity but low thermal stability.Besides,the poor formability of NiS_(2)powders also restricts the cathode performance of thermal batteries.In this paper,the novel NiS_(2)/SiO_(2)composite material was developed by high temperature vulcanization to improve the thermal stability formability of NiS_(2).The good filling and lubrication of spherical SiO_(2)can improve the thermal conductivity of NiS_(2)electrode.The discharge test shows that the NiS_(2)/SiO_(2)cathode has a stable discharge voltage at a current density of 200 mA/cm^(2),and the activation time is shortened by nearly 20%compared with the NiS_(2)cathode.In addition,due to the favorable thermal insulation protection of SiO_(2),the initial decomposition temperature of NiS_(2)is increased by 30℃after the addition of SiO_(2).The incorporation of SiO_(2)not only effectively improves the thermal stability and electrochemical properties of NiS_(2),but also improves the cold pressing forming performance of the NiS_(2)powder.Therefore,the novel NiS_(2)/SiO_(2)composite material is more suitable for thermal batteries with high stability and fast response,which is of great significance for improving the maneuverability and quality reliability of weapons and equipment.展开更多
The Li-CO_(2)battery has been highly rated as an intriguing technique for balancing the carbon cycle for years,but it is still significantly challenged by the obstacles such as limited reversibility,sluggish kinetics,...The Li-CO_(2)battery has been highly rated as an intriguing technique for balancing the carbon cycle for years,but it is still significantly challenged by the obstacles such as limited reversibility,sluggish kinetics,and poor energy efficiency.Hence,the design and development of advance catalysts that can enhance the kinetics and reversibility of the CO_(2)electrochemical cycling reactions are considered the imperative tasks.Transition metal-based catalysts are widely considered appealing owing to their unfilled dorbitals,rich and adjustable valences,as well as processibility.In this review,the working mechanism and the key issues of the CO_(2)electrochemical cycling reaction are discussed first.Then the strategies for composition and structure design of different type of transition metal-based catalysts are highlighted,including their benefits,limitations,and the ways to implement these strategies.Finally,based on the pioneering research,the perspectives on the challenges and key points for the future development of cathode catalyst are proposed.展开更多
PrBaFe_(2)O_(5+δ)(PBF)is one of the promising cathode materials for intermediate-temperature solid oxide fuel cell(IT-SOFC)technology.However,as the operating temperature decreases,the electrochemical performance of ...PrBaFe_(2)O_(5+δ)(PBF)is one of the promising cathode materials for intermediate-temperature solid oxide fuel cell(IT-SOFC)technology.However,as the operating temperature decreases,the electrochemical performance of this material deteriorates rapidly.To counter this,various doping strategies have been tested and reported in order to improve the electrochemical properties of this material at intermediate-temperatures.In this study,Mg-doping to partially substitute Fe of PBF was investigated.PrBaFe_(2-x)Mg_(x)O_(5+δ)(PBFMgx,x=0.1,0.15,0.2,0.3)materials were successfully synthesized,and their electrochemical performance as IT-SOFC cathode was evaluated.It is shown that Mg-doping enhances the conductivity of PBF between 650 and 800℃,impacts little on the area-specific resistance of oxygen reduction reaction at and above 700℃,and,most significantly,improves the power density of the NiSDC/SDC/PBFMg0.15single cell by 52%compared to the un-doped PBF.This enhanced electrochemical performance is attributed to the improvement in PBF conductivity by Mg-doping.展开更多
The performance of solid oxide electrolysis cells(SOECs)for CO_(2) electrolysis is significantly impeded by the limited electrochemical activity and insufficient durability of the cathode.This study introduces a novel...The performance of solid oxide electrolysis cells(SOECs)for CO_(2) electrolysis is significantly impeded by the limited electrochemical activity and insufficient durability of the cathode.This study introduces a novel(LaSrPrBaCaGd)_(2)Fe_(1.5)Mo_(0.5)O_(6-δ)(LSPBCGFM)perovskite via A-site entropy engineering,to improve both activity and durability.Experimental results reveal that LSPBCGFM cathode-based SOEC achieves a current density of 1.34 A·cm^(−2) at 1.5 V and 800℃,maintaining stable operation for more than 400 h at 1.2 V with negligible degradation.Theoretical calculations suggest that the high-entropy strategy shifts the transition metal d-band center and O-2p-band center closer to the Fermi energy level simultaneously,thereby initiating more favorable CO_(2) adsorption and activation.In addition,a higher O-2p-band center promotes the formation and diffusion of oxygen vacancies.The findings of this study provide crucial insights into the role of conformational entropy strategies in CO_(2) electrolysis and offer potential pathways for the development of highly efficient and stable catalysts.展开更多
The insufficient electrocatalytic activity and CO_(2)resistance hinder the application of cathode mate-rial for solid oxide fuel cells(SOFCs).In this study,we introduce a series of Pr-doped perovskite Bi_(0.8-x)Pr_(x)...The insufficient electrocatalytic activity and CO_(2)resistance hinder the application of cathode mate-rial for solid oxide fuel cells(SOFCs).In this study,we introduce a series of Pr-doped perovskite Bi_(0.8-x)Pr_(x)Ca_(0.2)FeO_(3-δ)(BPCF_(x),x=0,0.10,0.15,0.20)as candidate cathode materials,with a focus on its phase structure,oxygen desorption ability,catalytic activity,and electrochemical reduction kinetics.Among all the components,the Bi_(0.6)Pr_(0.2)Ca_(0.2)FeO_(3-δ)(BPCF0.20)catalyst shows impressive oxygen reduc-tion reaction(ORR)activity,with a low polarization resistance of 0.06Ωcm^(2)at 700℃and peak power density of 810 mW cm^(−2)at 800℃.Moreover,the BPCF0.20 cathode shows outstanding CO_(2)resistance in different CO_(2)concentrations(1%-10%)due to the larger average bond energy and higher relative acidity of Bi,Pr,and Fe ions.These findings demonstrate that BPCF_(x)are advanced cathode electrocatalysts for SOFCs.展开更多
CO_(2)electrolysis using solid oxide electrolysis cells is a promising technology for CO_(2)utilization and conversion,which has attracted more and more attention in recent years because of its extremely high efficien...CO_(2)electrolysis using solid oxide electrolysis cells is a promising technology for CO_(2)utilization and conversion,which has attracted more and more attention in recent years because of its extremely high efficiency.However,traditional Ni-yttria-stabilized zirconia(Ni-YSZ)or Ni-Gd_(0.1)Ce_(0.9)O_(2-δ)(Ni-GDC)metal-ceramic cathode faces many problems such as Ni agglomeration and carbon deposition during long-time operation.Herein,a perovskite oxide La_(0.43-x)Ca_(0.37)Ti_(0.9)Ni_(0.1)O_(3-δ)(LCTN,x=0,0.05,0.1)with nanophase-LaVO_(4)exsolution was investigated as the novel cathode of solid oxide electrolysis cell(SOEC)for efficient CO_(2)electrolysis.The results confirm that the exsolution nanophase on LCTN surface can significantly improve the CO_(2)adsorption and conversion performance.For CO_(2)electrolysis at 1.8 V,an electrolysis current density of 1.24 A/cm2at 800℃can be obtained on SOEC with La_(0.43-x)Ca_(0.37)Ti_(0.9)Ni_(0.1)O_(3-δ)decorated with LaVO_(4)(LCTN-V0.05)cathode.Furthermore,the corresponding cell can maintain stable operation up to 100 h without apparent performance degradation.These results demonstrate that doping-induced second nanophase exsolution is a promising way to design high-performance SOEC cathodes for CO_(2)electrolysis.展开更多
Ni-rich cathodes(Ni≥70%)with high specific capacities emerge as promising candidates for long-range lithium-ion batteries(LIBs).Nevertheless,their practical application is severely limited by two unresolved challenge...Ni-rich cathodes(Ni≥70%)with high specific capacities emerge as promising candidates for long-range lithium-ion batteries(LIBs).Nevertheless,their practical application is severely limited by two unresolved challenges:structural degradation from uncontrolled Li/Ni mixing and interfacial instability exacerbated by air/electrolyte corrosion.Herein,we propose a dual-modulation strategy to synthesize a stable Ni-rich cathode via carboxylate-based metal-organic frameworks(MOFs)-derived precursors,whereby oxygen vacancies in the precursors induce controlled moderate Li/Ni mixing,while their enhanced specific-surface-area property enables dense amorphous Li_(2)CO_(3)encapsulation.The optimal Li/Ni mixing harnesses the Ni pillar effect to stabilize the structure of cathodes upon cycling.Additionally,amorphous Li_(2)CO_(3)coating serves not only as a thermodynamically stable and air-impermeable protective layer for the cathodes,but as a transformative precursor for an F-rich cathode electrolyte interphase(CEI)which enhances interfacial stability and electrochemical properties.This dual-modulated cathode delivers a high discharge capacity of 215.1 mA h g^(-1)at 0.1 C,retains 84.9% capacity after 200 cycles at 1 C in half cells,and achieves 96.0 mA h g^(-1)at 8 C in full-cell tests.Furthermore,we unravel the potential mechanism of Ni pillar effect from optimal Li/Ni mixing and track the evolution mechanism of Li_(2)CO_(3)coating into F-rich CEI.This work offers advanced perspectives for the controllable cation disordering engineering and rational design of surface residual lithium compounds in Ni-rich cathodes,thereby providing new guiding principles for protecting high-capacity cathodes in energy storage devices.展开更多
Na_(3)V_(2)(PO_(4))_(3)(NVP)is regarded as alternative cathode material for sodium-ion batteries(SIBs)due to its potential high-rate performance and pronounced long-term cycle stability.However,electronic conductivity...Na_(3)V_(2)(PO_(4))_(3)(NVP)is regarded as alternative cathode material for sodium-ion batteries(SIBs)due to its potential high-rate performance and pronounced long-term cycle stability.However,electronic conductivity and tap density are difficult to be balanced.Herein,we report that high-temperature shock(HTS)can prepare“single crystalline like”NVP which combines high-rate capability with high tap density together into one with the assistance of carbon framework and large particle.Thus,high reversible capacity of 110m Ah/g at 0.1 C with 89.9%capacity retention after 1600 cycles at 1 C and specific capacity of 83.5 m Ah/g at 50 C rate has been exhibited.This study provides a novel strategy to guide the production of high tap density,and rate performance polyanionic cathode materials.展开更多
To address the challenges of air stability and slurry processability in layered transition metal oxide O_(3)-type NaNi_(1/3)Fe_(1/3)Mn_(1/3)O_(2)(NFM)for sodium-ion batteries(SIBs),we have designed an innovative 500℃...To address the challenges of air stability and slurry processability in layered transition metal oxide O_(3)-type NaNi_(1/3)Fe_(1/3)Mn_(1/3)O_(2)(NFM)for sodium-ion batteries(SIBs),we have designed an innovative 500℃reheating strategy.This method improves the surface properties of NFM without the need for additional coating layers,making it more efficient and suitable for large-scale applications.Pristine NFM(NFM-P)was first synthesized through a high-temperature solid-state method and then modified using this reheating approach(NFM-HT).This strategy significantly enhances air stability and electrochemical performance,yielding an initial discharge specific capacity of 151.46 mAh/g at 0.1C,with a remarkable capacity retention of 95.04%after 100 cycles at 0.5C.Additionally,a 1.7 Ah NFM‖HC(hard carbon)pouch cell demonstrates excellent long-term cycling stability(94.64%retention after 500 cycles at 1C),superior rate capability(86.48%retention at 9C),and strong low-temperature performance(77%retention at-25℃,continuing power supply at-40℃).Notably,even when overcharged to 8.29 V,the pouch cell remained safe without combustion or explosion.This reheating strategy,which eliminates the need for a coating layer,offers a simpler,more scalable solution for industrial production while maintaining outstanding electrochemical performance.These results pave the way for broader commercial adoption of NFM materials.展开更多
Mixed polyanion phosphate Na_(4)Fe_(3)(PO_(4))_(2)P_(2)O_(7)(NFPP)is regarded as the most promising cathode material for sodium-ion batteries(SIBs),due to its high structural stability and low-cost environmental frien...Mixed polyanion phosphate Na_(4)Fe_(3)(PO_(4))_(2)P_(2)O_(7)(NFPP)is regarded as the most promising cathode material for sodium-ion batteries(SIBs),due to its high structural stability and low-cost environmental friendliness.However,its intrinsic low conductivity and sluggish Na^(+)diffusion restricted the fast-charge and low-temperature sodium storage.Herein,an NFPP composite encapsulated by in-situ pyrolytic carbon and coupled with expanded graphite(NFPP@C/EG)was constructed via a sol-gel method followed by a ballmill procedure.Due to the dual-carbon modified strategy,this NFPP@C/EG only enhanced the electronic conductivity,but also endowed more channels for Na^(+)diffusion.As cathode for SIBs,the optimized NFPP(M-NFPP@C/EG)delivers excellent rate capability(capacity of~80.5 mAh/g at 50 C)and outstanding cycling stability(11000 cycles at 50 C with capacity retention of 89.85%).Additionally,cyclic voltammetry(CV)confirmed that its sodium storage behavior is pseudocapacitance-controlled,with in-situ electrochemical impedance spectroscopy(EIS)further elucidating improvements in electrode reaction kinetics.At lower temperatures(0℃),M-NFPP@C/EG demonstrated exceptional cycling performance(8800 cycles at 10 C with capacity retention of 95.81%).Moreover,pouch cells also exhibited excellent stability.This research demonstrates the feasibility of a dual carbon modification strategy in enhancing NFPP and proposes a low-cost,high-rate,and ultra-stable cathode material for SIBs.展开更多
As a potential candidate for high-energy lithium-ion batteries (LIBs),nickel-rich cathodes encounter significant challenges due to structural instability arising from interphases.In this work,tris(ethenyl)-tris(etheny...As a potential candidate for high-energy lithium-ion batteries (LIBs),nickel-rich cathodes encounter significant challenges due to structural instability arising from interphases.In this work,tris(ethenyl)-tris(ethenyl)silyloxysilane (HVDS) with Si–O bonds and unsaturated bonds is introduced as additive designing functional electrolyte to enhance the long-cycle stability of LiNi_(0.8)Co_(0.1)Mn_(0.1)O_(2)(NCM811)/graphite LIBs at elevated temperature.The preferential oxidization and component of HVDS facilitate the generation of an extremely robust and ultra-thin cathode electrolyte interphase (CEI) comprising a chemically bonded silane polymer.This interphase effectively suppresses side-reactions of electrolyte,mitigates HF erosion,and reduces irreversible phase transitions.Benefiting from the above merits,the batteries’capacity retention shows a remarkable increase from 20% to 92% after nearly 1550 cycles conducted at room temperature.And under elevated temperature conditions (45℃),the capacity retention remains 80%after 670 cycles,in comparison to a drop to 80%after only 250 cycles with the blank electrolyte.These findings highlight HVDS’s potential to functionalize the electrolyte,marking a breakthrough in improving the longevity and reliability of NCM811/graphite LIBs under challenging conditions.展开更多
基金National Natural Science Foundation of China,Grant/Award Number:51804173。
文摘Transition metal fluorides(TMFs)cathode materials have shown extraordinary promises for electrochemical energy storage,but the understanding of their electrochemical reaction mechanisms is still a matter of debate due to the complicated and continuous changing in the battery internal environment.Here,we design a novel iron fluoride(FeF_(2))aggregate assembled with cylindrical nanoparticles as cathode material to build FeF_(2) lithium-ion batteries(LIBs)and employ advanced in situ magnetometry to detect their intrinsic electronic structure during cycling in real time.The results show that FeF_(2) cannot be involved in complete conversion reactions when the FeF_(2) LIBs operate between the conventional voltage range of 1.0–4.0 V,and that the corresponding conversion ratio of FeF_(2) can be further estimated.Importantly,we first demonstrate that the spin-polarized surface capacitance exists in the FeF_(2) cathode by monitoring the magnetic responses over various voltage ranges.The research presents an original and insightful method to examine the conversion mechanism of TMFs and significantly provides an important reference for the future artificial design of energy systems based on spinpolarized surface capacitance.
基金funding support from the National Natural Science Foundation of China(51804173)the Shandong Provincial Natural Science Foundation(ZR2018BB030)+1 种基金the Qingdao Science and Technology Plan Applied Basic Research(Youth Special Project,18-2-2-22-jch)the funding support from “Distinguished Taishan Scholar”project。
文摘Lithium-ion capacitors(LICs)are regarded as a good choice for next-generation energy storage devices,which are expected to exhibit high energy densities,high power densities,and ultra-long cycling stability.Nevertheless,only a few battery-type cathode materials with limited kinetic properties can be employed in LICs,and their electrochemical properties need to be optimized urgently.Here,we exploit a new dendrite-structured FeF_(2) consisting of closely linked primary nanoparticles using a facile solvothermal method combined with the subsequent annealing treatment.This particular architecture has favorable transport pathways for both lithium ions and electrons and exhibits an ultrafast chargedischarge capability with high reversible capacities.Furthermore,a well-designed LIC employing the prepared dendrite-structured FeF_(2) as the battery-type cathode and commercialized activated carbon(AC)as supercapacitor-type anode was constructed in an organic electrolyte containing Li ions.The LIC operates at an optimal voltage range of 1.1-3.8 V and shows a maximum high energy density of 152 W h kg^(-1) and a high power density of 4900 W kg^(-1) based on the total mass of cathode and anode.Long-term cycling stability(85%capacity retention after 2000 cycles)was achieved at 1 A g^(-1).This work suggests that the dendrite-structured FeF_(2) is a prime candidate for high-performance LICs and accelerates the development of hybrid ion capacitor devices.
基金supported by Foundation for the Sichuan University and Zigong City Joint research project(2021CDZG-2)the Foundation for the Sichuan University and Yibin City Strategic Cooperation Project(2020CDYB-32)the Guangxi Key Laboratory of Low Carbon Energy Material(2020GKLLCEM02)。
文摘Fluoride ferrous(FeF_(2))is viewed as a promising conversion cathode material for next-generation lithiumion batteries(LIBs)due to its high theoretical specific capacity and low cost.Unfortunately,issues such as poor intrinsic conductivity,iron dissolution,and phase separation hinder the application of FeF_(2)in highenergy cathodes.Here,a pressure-induced morphology control method is designed to prepare coralloidlike FeF_(2)nanocrystals with nitrogen-rich carbon coating(c-FeF_(2)@NC).The coralloid-like interconnected crystal structure of c-FeF_(2)@NC contributes to reducing interfacial resistance and enhancing the topotactic transformation during the conversion reaction,and the nitrogen-rich carbon(NC)coating can enhance interfacial stability and kinetic performance.When used as a conversion cathode for LIBs,c-FeF_(2)@NC exhibits a high initial reversible capacity of 503.57 mA h g^(-1)and excellent cycling stability of497.61 m A h g^(-1)with a low capacity decay of 1.19%over 50 cycles at 0.1 A/g.Even at 1 A/g,a stable capacity of 263.78 mA h g^(-1)can still be retained after 200 cycles.The capability of c-FeF_(2)@NC as a conversion cathode for sodium-ion batteries(SIBs)was also evaluated to expand its field of application.Furthermore,two kinds of full batteries have been assembled by employing c-FeF_(2)@NC as cathodes and quantitative limited-Li(LLi)and pre-lithiated reduced graphene oxide(PGO)as anodes,respectively,to envisage the feasibility of practical applications of conversion materials.
基金partly supported by the National Natural Science Foundation of China(Grant No.52272225).
文摘Na_(3)V_(2)(PO_(4))_(3)(NVP)has garnered great attentions as a prospective cathode material for sodium-ion batteries(SIBs)by virtue of its decent theoretical capacity,superior ion conductivity and high structural stability.However,the inherently poor electronic conductivity and sluggish sodium-ion diffusion kinetics of NVP material give rise to inferior rate performance and unsatisfactory energy density,which strictly confine its further application in SIBs.Thus,it is of significance to boost the sodium storage performance of NVP cathode material.Up to now,many methods have been developed to optimize the electrochemical performance of NVP cathode material.In this review,the latest advances in optimization strategies for improving the electrochemical performance of NVP cathode material are well summarized and discussed,including carbon coating or modification,foreign-ion doping or substitution and nanostructure and morphology design.The foreign-ion doping or substitution is highlighted,involving Na,V,and PO_(4)^(3−)sites,which include single-site doping,multiple-site doping,single-ion doping,multiple-ion doping and so on.Furthermore,the challenges and prospects of high-performance NVP cathode material are also put forward.It is believed that this review can provide a useful reference for designing and developing high-performance NVP cathode material toward the large-scale application in SIBs.
基金supported by the Significant Science and Technology Project in Xiamen(Future Industry Field)(Grant No.3502Z20231057).
文摘Lithium nickel oxide(Li_(2)NiO_(2)),as a sacrificial cathode prelithiation additive,has been used to compensate for the lithium loss for improving the lifespan of lithium-ion batteries(LIBs).However,high-cost Li_(2)NiO_(2)suffers from inferior delithiation kinetics during the first cycle.Herein,we investigated the effects of the cost-effective copper substituted Li_(2)Ni_(1-x)Cu_(x)O_(2)(x=0,0.2,0.3,0.5,0.7)synthesized by a high-temperature solid-phase method on the structure,morphology,electrochemical performance of graphite‖LiFePO_(4)battery.The X-ray diffraction(XRD)refinement result demonstrated that Cu substitution strategy could be favorable for eliminating the NiO_(x)impurity phase and weakening Li-O bond.Analysis on density of states(DOS)indicates that Cu substitution is good for enhancing the electronic conductivity,as well as reducing the delithi-ation voltage polarization confirmed by electrochemical characterizations.Therefore,the optimal Li_(2)Ni_(0.7)Cu_(0.3)O_(2)delivered a high delithiation capacity of 437 mAh·g^(-1),around 8%above that of the pristine Li_(2)NiO_(2).Furthermore,a graphite‖LiFePO_(4)pouch cell with a nominal capacity of 3000 mAh demonstrated a notably improved reversible capacity,energy density and cycle life through introducing 2 wt%Li_(2)Ni_(0.7)Cu_(0.3)O_(2)additive,delivering a 6.2 mAh·g^(-1)higher initial discharge capacity and achieving around 5%improvement in capacity retentnion at 0.5P over 1000 cycles.Additionally,the post-mortem analyses testified that the Li_(2)Ni_(0.7)Cu_(0.3)O_(2)additive could suppress solid electrolyte interphase(SEI)decomposition and homogenize the Li distribution,which benefits to stabilizing interface between graphite and electrolyte,and alleviating dendritic Li plating.In conclusion,the Li_(2)Ni_(0.7)Cu_(0.3)O_(2)additive may offer advantages such as lower cost,lower delithiation voltage and higher prelithiation capacity compared with Li_(2)NiO_(2),making it a promising candidate of cathode prelithiation additive for next-generation LIBs.
基金supported by National Natural Science Youth Foundation of China(No.22308294)National Natural Science Foundation of China(No.22179077)+1 种基金Postgraduate Research&Practice Innovation Program of Jiangsu Province(No.SJCX23_1868)Qing Lan Project of Jiangsu University and the Funding for school-level research projects of Yancheng Institute of Technology.
文摘Mn-based P2-type oxides are considered as promising cathodes for Na-ion batteries;however,they face significant challenges,including structural degradation when charged at high cutoff voltages and structural changes upon storing in a humid atmosphere.In response to these issues,we have designed an oxide with co-doping of Cu and Al which can balance both cost and structural stability.The redox reaction of Cu^(2+/3+)can provide certain charge compensation,and the introduction of Al can further suppress the Jahn-Teller effect of Mn,thereby achieving superior long-term cycling performance.The ex-situ XRD testing indicates that Cu/Al co-doping can effectively suppress the phase transition of P2-O2 at high voltage,thereby explaining the improvement in electrochemical performance.DFT calculations reveal a high chemical tolerance to moisture,with lower adsorption energy for H_(2)O compared to pure Na_(0.67)Cu_(0.25)Mn_(0.75)O_(2).A representative Na_(0.67)Cu_(0.20)Al_(0.05)Mn_(0.75)O_(2)cathode demonstrates impressive reversible capacities of 148.7 mAh/g at 0.2 C,along with a remarkable capacity retention of 79.1%(2 C,500 cycles).
基金supported by the Scientific Research Fund of Hunan Provincial Education Department,China(No.22B0741)。
文摘The electrochemical performance of layered O3-type NaCrO_(2)cathode material is significantly affected by the side reactions between NaCrO_(2)and electrolyte during sodium storage.A uniform Cr_(2)O_(3)coating layer was in situ constructed on the surface of NaCrO_(2)by controlling the excess ratio of sodium source.The structure,morphology,valence and electrochemical performance of the Cr_(2)O_(3)-coated NaCrO_(2)were characterized.The results indicate that the Cr_(2)O_(3)coating layer does not alter the crystal structure and morphology of NaCrO_(2),but effectively suppresses the side reactions between NaCrO_(2)and electrolyte,and improves the surface/interfacial stability of NaCrO_(2)material.The Cr_(2)O_(3)-coated NaCrO_(2)exhibits improved electrochemical performance with a capacity retention of 66.4%after 500 cycles at 10C.
基金Project supported by the National Key Research and Development Program of China (Grant No. 2022YFB2404400)。
文摘LiMn_(2)O_(4)(LMO) represents one of the most prevalent cathode materials utilized in lithium-ion batteries(LIBs), yet its broader application is often hampered by its limited achievable capacity and significant capacity degradation during cycling. In this work, a novel dual-doping strategy involving Al^(3+) and Zr^(4+) ions has been employed to refine the atomic structure of LMO's spinel framework. The resultant dual-doped material, Li_(1.06)Mn_(1.97)Zr_(0.01)Al_(0.02)O_(4), exhibits enhanced electrochemical properties, boasting a discharge capacity of 124.9 m Ah/g at a rate of 0.1 C. Furthermore, the formation of stronger Al–O and Zr–O bonds contributes to the stabilization of the delithiated LMO structure. Impressively, 97.7%of its initial capacity is retained after 100 cycles at a 5 C rate. Additionally, enhancements in rate performance and hightemperature cycling stability have also been observed. This study underscores the potential of Al^(3+) and Zr^(4+) dual-doping as a promising approach to enhance LMO cathodes, providing a scalable and efficient means of improving the performance of lithium manganese oxide cathode materials through the incorporation of multiple ions.
基金supported by the National Key Research and Development Program of China(2022YFB2502103)the Xiamen Science and Technology Project(No.3502Z20231057)+2 种基金the National Natural Science Foundation of China(No.22288102,No.22279107,No.22309153)the Fujian Provincial Natural Science Foundation of China(No.2024J01040)the Fundamental Research Funds for the Central Universities(No.20720230039)。
文摘Extending the charging voltage of LiCoO_(2)(LCO)is an ongoing and promising approach to increase its energy density.However,the main challenge of the approach lies in the insuperable cathodic interfacial processes at high voltage,which leads to rapid failure both in the performance and structure of the LCO cathode.Herein,a Li_(2)CO_(3)-based additive was prepared by a simple sand-milling method,enabling a low electrochemical decomposition voltage<4.6 V from commonly>4.8 V,stabilizing the interface of the LCO cathode at 4.6 V.The decomposition of Li_(2)CO_(3)provides extra Li^(+)and CO_(2)to supplement the Li consumption required in the initial irreversible interfacial reactions and rapidly form a uniform and stable cathode electrolyte interphase layer(less organic and more inorganic components)on the LCO cathode by reducing CO_(2).Thus,the phase transformation and the emergence of high-valent Co ions on the surface of LCO at 4.6 V high voltage were inhibited.Thanks to this,with 2%Li_(2)CO_(3)-based additive,the capacity retention of commercial LCO at a high voltage of 4.6 V at 0.5 C for 100 cycles was improved from 59.3%to 79.3%.This work improves the high-voltage stability of LCO and provides a new idea for realizing the high-voltage operation of batteries.
基金Project(23JCYBJC01870)supported by the Natural Science Foundation of Tianjin,ChinaProject(U22A20119)supported by the National Natural Science Foundation of China。
文摘As a cathode material for thermal batteries,NiS_(2)has a high theoretical capacity but low thermal stability.Besides,the poor formability of NiS_(2)powders also restricts the cathode performance of thermal batteries.In this paper,the novel NiS_(2)/SiO_(2)composite material was developed by high temperature vulcanization to improve the thermal stability formability of NiS_(2).The good filling and lubrication of spherical SiO_(2)can improve the thermal conductivity of NiS_(2)electrode.The discharge test shows that the NiS_(2)/SiO_(2)cathode has a stable discharge voltage at a current density of 200 mA/cm^(2),and the activation time is shortened by nearly 20%compared with the NiS_(2)cathode.In addition,due to the favorable thermal insulation protection of SiO_(2),the initial decomposition temperature of NiS_(2)is increased by 30℃after the addition of SiO_(2).The incorporation of SiO_(2)not only effectively improves the thermal stability and electrochemical properties of NiS_(2),but also improves the cold pressing forming performance of the NiS_(2)powder.Therefore,the novel NiS_(2)/SiO_(2)composite material is more suitable for thermal batteries with high stability and fast response,which is of great significance for improving the maneuverability and quality reliability of weapons and equipment.
基金financially supported by the National Natural Science Foundation of China(52201254,52234001,52074177)the National Key Research and Development Program(2022YFC3900905)+3 种基金the Natural Science Foundation of Shandong Province(ZR2020QE012,ZR2020MB090,ZR2023ME155,ZR2023ME085)the Scientific Research Foundation for New Talents in University of Jinan(XRC2406)the project of “20 Items of University”of Jinan(202228046)the Introducing Major Universities and Research Institutions to Jointly Build Innovative Carrier Project of Jining City(2023DYDS022)。
文摘The Li-CO_(2)battery has been highly rated as an intriguing technique for balancing the carbon cycle for years,but it is still significantly challenged by the obstacles such as limited reversibility,sluggish kinetics,and poor energy efficiency.Hence,the design and development of advance catalysts that can enhance the kinetics and reversibility of the CO_(2)electrochemical cycling reactions are considered the imperative tasks.Transition metal-based catalysts are widely considered appealing owing to their unfilled dorbitals,rich and adjustable valences,as well as processibility.In this review,the working mechanism and the key issues of the CO_(2)electrochemical cycling reaction are discussed first.Then the strategies for composition and structure design of different type of transition metal-based catalysts are highlighted,including their benefits,limitations,and the ways to implement these strategies.Finally,based on the pioneering research,the perspectives on the challenges and key points for the future development of cathode catalyst are proposed.
基金supported by the National Natural Science Foundation of China(51974167)Natural Science Foundation Youth Foundation of Inner Mongolia(2023QN05038)Higher Education Carbon Peak Carbon Neutral Research Project of Inner Mongolia Autonomous Region(STZX202210)。
文摘PrBaFe_(2)O_(5+δ)(PBF)is one of the promising cathode materials for intermediate-temperature solid oxide fuel cell(IT-SOFC)technology.However,as the operating temperature decreases,the electrochemical performance of this material deteriorates rapidly.To counter this,various doping strategies have been tested and reported in order to improve the electrochemical properties of this material at intermediate-temperatures.In this study,Mg-doping to partially substitute Fe of PBF was investigated.PrBaFe_(2-x)Mg_(x)O_(5+δ)(PBFMgx,x=0.1,0.15,0.2,0.3)materials were successfully synthesized,and their electrochemical performance as IT-SOFC cathode was evaluated.It is shown that Mg-doping enhances the conductivity of PBF between 650 and 800℃,impacts little on the area-specific resistance of oxygen reduction reaction at and above 700℃,and,most significantly,improves the power density of the NiSDC/SDC/PBFMg0.15single cell by 52%compared to the un-doped PBF.This enhanced electrochemical performance is attributed to the improvement in PBF conductivity by Mg-doping.
基金supported by the National Natural Science Foundation of China(Nos.22379133,22075256,and 52072350)the Natural Science Foundation of Guangdong Province(No.2024A1515012235).
文摘The performance of solid oxide electrolysis cells(SOECs)for CO_(2) electrolysis is significantly impeded by the limited electrochemical activity and insufficient durability of the cathode.This study introduces a novel(LaSrPrBaCaGd)_(2)Fe_(1.5)Mo_(0.5)O_(6-δ)(LSPBCGFM)perovskite via A-site entropy engineering,to improve both activity and durability.Experimental results reveal that LSPBCGFM cathode-based SOEC achieves a current density of 1.34 A·cm^(−2) at 1.5 V and 800℃,maintaining stable operation for more than 400 h at 1.2 V with negligible degradation.Theoretical calculations suggest that the high-entropy strategy shifts the transition metal d-band center and O-2p-band center closer to the Fermi energy level simultaneously,thereby initiating more favorable CO_(2) adsorption and activation.In addition,a higher O-2p-band center promotes the formation and diffusion of oxygen vacancies.The findings of this study provide crucial insights into the role of conformational entropy strategies in CO_(2) electrolysis and offer potential pathways for the development of highly efficient and stable catalysts.
基金supported by the Natural Science Foundation of Heilongjiang Province(No.ZD2022E007).
文摘The insufficient electrocatalytic activity and CO_(2)resistance hinder the application of cathode mate-rial for solid oxide fuel cells(SOFCs).In this study,we introduce a series of Pr-doped perovskite Bi_(0.8-x)Pr_(x)Ca_(0.2)FeO_(3-δ)(BPCF_(x),x=0,0.10,0.15,0.20)as candidate cathode materials,with a focus on its phase structure,oxygen desorption ability,catalytic activity,and electrochemical reduction kinetics.Among all the components,the Bi_(0.6)Pr_(0.2)Ca_(0.2)FeO_(3-δ)(BPCF0.20)catalyst shows impressive oxygen reduc-tion reaction(ORR)activity,with a low polarization resistance of 0.06Ωcm^(2)at 700℃and peak power density of 810 mW cm^(−2)at 800℃.Moreover,the BPCF0.20 cathode shows outstanding CO_(2)resistance in different CO_(2)concentrations(1%-10%)due to the larger average bond energy and higher relative acidity of Bi,Pr,and Fe ions.These findings demonstrate that BPCF_(x)are advanced cathode electrocatalysts for SOFCs.
基金Project supported by the National Key Research&Development Project(2023YFB4006001)National Natural Science Foundation of China(52172199)。
文摘CO_(2)electrolysis using solid oxide electrolysis cells is a promising technology for CO_(2)utilization and conversion,which has attracted more and more attention in recent years because of its extremely high efficiency.However,traditional Ni-yttria-stabilized zirconia(Ni-YSZ)or Ni-Gd_(0.1)Ce_(0.9)O_(2-δ)(Ni-GDC)metal-ceramic cathode faces many problems such as Ni agglomeration and carbon deposition during long-time operation.Herein,a perovskite oxide La_(0.43-x)Ca_(0.37)Ti_(0.9)Ni_(0.1)O_(3-δ)(LCTN,x=0,0.05,0.1)with nanophase-LaVO_(4)exsolution was investigated as the novel cathode of solid oxide electrolysis cell(SOEC)for efficient CO_(2)electrolysis.The results confirm that the exsolution nanophase on LCTN surface can significantly improve the CO_(2)adsorption and conversion performance.For CO_(2)electrolysis at 1.8 V,an electrolysis current density of 1.24 A/cm2at 800℃can be obtained on SOEC with La_(0.43-x)Ca_(0.37)Ti_(0.9)Ni_(0.1)O_(3-δ)decorated with LaVO_(4)(LCTN-V0.05)cathode.Furthermore,the corresponding cell can maintain stable operation up to 100 h without apparent performance degradation.These results demonstrate that doping-induced second nanophase exsolution is a promising way to design high-performance SOEC cathodes for CO_(2)electrolysis.
基金the financial support from the Special Funds for the Cultivation of Guangdong College Students’Scientific and Technological Innovation(“Climbing Program”Special Funds,pdjh2024a109)。
文摘Ni-rich cathodes(Ni≥70%)with high specific capacities emerge as promising candidates for long-range lithium-ion batteries(LIBs).Nevertheless,their practical application is severely limited by two unresolved challenges:structural degradation from uncontrolled Li/Ni mixing and interfacial instability exacerbated by air/electrolyte corrosion.Herein,we propose a dual-modulation strategy to synthesize a stable Ni-rich cathode via carboxylate-based metal-organic frameworks(MOFs)-derived precursors,whereby oxygen vacancies in the precursors induce controlled moderate Li/Ni mixing,while their enhanced specific-surface-area property enables dense amorphous Li_(2)CO_(3)encapsulation.The optimal Li/Ni mixing harnesses the Ni pillar effect to stabilize the structure of cathodes upon cycling.Additionally,amorphous Li_(2)CO_(3)coating serves not only as a thermodynamically stable and air-impermeable protective layer for the cathodes,but as a transformative precursor for an F-rich cathode electrolyte interphase(CEI)which enhances interfacial stability and electrochemical properties.This dual-modulated cathode delivers a high discharge capacity of 215.1 mA h g^(-1)at 0.1 C,retains 84.9% capacity after 200 cycles at 1 C in half cells,and achieves 96.0 mA h g^(-1)at 8 C in full-cell tests.Furthermore,we unravel the potential mechanism of Ni pillar effect from optimal Li/Ni mixing and track the evolution mechanism of Li_(2)CO_(3)coating into F-rich CEI.This work offers advanced perspectives for the controllable cation disordering engineering and rational design of surface residual lithium compounds in Ni-rich cathodes,thereby providing new guiding principles for protecting high-capacity cathodes in energy storage devices.
基金supported by the National Natural Science Foundation of China(No.22109091)Natural Science Foundation of Shandong Province(No.ZR2021QB180)。
文摘Na_(3)V_(2)(PO_(4))_(3)(NVP)is regarded as alternative cathode material for sodium-ion batteries(SIBs)due to its potential high-rate performance and pronounced long-term cycle stability.However,electronic conductivity and tap density are difficult to be balanced.Herein,we report that high-temperature shock(HTS)can prepare“single crystalline like”NVP which combines high-rate capability with high tap density together into one with the assistance of carbon framework and large particle.Thus,high reversible capacity of 110m Ah/g at 0.1 C with 89.9%capacity retention after 1600 cycles at 1 C and specific capacity of 83.5 m Ah/g at 50 C rate has been exhibited.This study provides a novel strategy to guide the production of high tap density,and rate performance polyanionic cathode materials.
基金the financial support provided by the Longzihu New Energy Laboratory Joint Fund of Henan Province(2023008)the Energy Storage Mater.and Processes Key Laboratory of Henan Province Open Fund(2021003)+1 种基金the Collaborative Innovation Team Project Fund of Industry-University-Research(32214085)the financial support received from Zhejiang Vast Na Technology Co.,Ltd.(24110380)。
文摘To address the challenges of air stability and slurry processability in layered transition metal oxide O_(3)-type NaNi_(1/3)Fe_(1/3)Mn_(1/3)O_(2)(NFM)for sodium-ion batteries(SIBs),we have designed an innovative 500℃reheating strategy.This method improves the surface properties of NFM without the need for additional coating layers,making it more efficient and suitable for large-scale applications.Pristine NFM(NFM-P)was first synthesized through a high-temperature solid-state method and then modified using this reheating approach(NFM-HT).This strategy significantly enhances air stability and electrochemical performance,yielding an initial discharge specific capacity of 151.46 mAh/g at 0.1C,with a remarkable capacity retention of 95.04%after 100 cycles at 0.5C.Additionally,a 1.7 Ah NFM‖HC(hard carbon)pouch cell demonstrates excellent long-term cycling stability(94.64%retention after 500 cycles at 1C),superior rate capability(86.48%retention at 9C),and strong low-temperature performance(77%retention at-25℃,continuing power supply at-40℃).Notably,even when overcharged to 8.29 V,the pouch cell remained safe without combustion or explosion.This reheating strategy,which eliminates the need for a coating layer,offers a simpler,more scalable solution for industrial production while maintaining outstanding electrochemical performance.These results pave the way for broader commercial adoption of NFM materials.
基金supported by the National Key Research and Development Program of China(No.2022YFB2502000)the National Natural Science Foundation of China(Nos.U21A20332,51771076,U21A200970,52301266)the Science and Technology Planning Project of Guangzhou(No.2024A04J3332)。
文摘Mixed polyanion phosphate Na_(4)Fe_(3)(PO_(4))_(2)P_(2)O_(7)(NFPP)is regarded as the most promising cathode material for sodium-ion batteries(SIBs),due to its high structural stability and low-cost environmental friendliness.However,its intrinsic low conductivity and sluggish Na^(+)diffusion restricted the fast-charge and low-temperature sodium storage.Herein,an NFPP composite encapsulated by in-situ pyrolytic carbon and coupled with expanded graphite(NFPP@C/EG)was constructed via a sol-gel method followed by a ballmill procedure.Due to the dual-carbon modified strategy,this NFPP@C/EG only enhanced the electronic conductivity,but also endowed more channels for Na^(+)diffusion.As cathode for SIBs,the optimized NFPP(M-NFPP@C/EG)delivers excellent rate capability(capacity of~80.5 mAh/g at 50 C)and outstanding cycling stability(11000 cycles at 50 C with capacity retention of 89.85%).Additionally,cyclic voltammetry(CV)confirmed that its sodium storage behavior is pseudocapacitance-controlled,with in-situ electrochemical impedance spectroscopy(EIS)further elucidating improvements in electrode reaction kinetics.At lower temperatures(0℃),M-NFPP@C/EG demonstrated exceptional cycling performance(8800 cycles at 10 C with capacity retention of 95.81%).Moreover,pouch cells also exhibited excellent stability.This research demonstrates the feasibility of a dual carbon modification strategy in enhancing NFPP and proposes a low-cost,high-rate,and ultra-stable cathode material for SIBs.
基金financially supported by the Scientific Research Innovation Project of Graduate School of South China Normal University (No. 2024KYLX081)。
文摘As a potential candidate for high-energy lithium-ion batteries (LIBs),nickel-rich cathodes encounter significant challenges due to structural instability arising from interphases.In this work,tris(ethenyl)-tris(ethenyl)silyloxysilane (HVDS) with Si–O bonds and unsaturated bonds is introduced as additive designing functional electrolyte to enhance the long-cycle stability of LiNi_(0.8)Co_(0.1)Mn_(0.1)O_(2)(NCM811)/graphite LIBs at elevated temperature.The preferential oxidization and component of HVDS facilitate the generation of an extremely robust and ultra-thin cathode electrolyte interphase (CEI) comprising a chemically bonded silane polymer.This interphase effectively suppresses side-reactions of electrolyte,mitigates HF erosion,and reduces irreversible phase transitions.Benefiting from the above merits,the batteries’capacity retention shows a remarkable increase from 20% to 92% after nearly 1550 cycles conducted at room temperature.And under elevated temperature conditions (45℃),the capacity retention remains 80%after 670 cycles,in comparison to a drop to 80%after only 250 cycles with the blank electrolyte.These findings highlight HVDS’s potential to functionalize the electrolyte,marking a breakthrough in improving the longevity and reliability of NCM811/graphite LIBs under challenging conditions.
