The effects of FeS 2 on the discharge characteristics of Li B alloy/FeS 2 thermal battery had been studied. Results showed that 2.5%(mass fraction)Li 2O would be needed to rule out the voltage pulse in the first part ...The effects of FeS 2 on the discharge characteristics of Li B alloy/FeS 2 thermal battery had been studied. Results showed that 2.5%(mass fraction)Li 2O would be needed to rule out the voltage pulse in the first part of discharge curves for the FeS 2 powder of small particle size (<44 μm). After thermal decomposition, the FeS 2 had transformed to Fe (1- x ) S where x =0.024～0.066. The deficiency of the cathode FeS 2 would make discharge voltage decrease 0.4 V. In the discharge test at high temperature (600 ℃), the discharge voltage decreased fast with the acceleration of the thermal decomposition of FeS 2.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
Iron disulfide(FeS_(2))has been widely used in thermal batteries because of its high theoretical specific capacity and voltage plateau.However,low thermal decomposition temperature,poor conductivity and inferior actua...Iron disulfide(FeS_(2))has been widely used in thermal batteries because of its high theoretical specific capacity and voltage plateau.However,low thermal decomposition temperature,poor conductivity and inferior actual specific capacity limit its wide applications.Herein,we report a gold-doped FeS_(2)(FeS_(2)-Au),which not only reduces the band gap of the FeS_(2)crystals but also enriches the electron transport path of FeS_(2)by the formation of Au nanoparticles.First-principles calculation shows that the diffusion energy barrier of lithium-ion is reduced after the Au-doped FeS_(2).In addition,Au increases the electron cloud density around sulfur atoms,which helps to enhance the stability of Fe-S covalent bonds and thus results in better thermal stability of FeS_(2).When the Au content is 130μg·g^(-1)(FeS_(2)-Au_(4)),the thermal decomposition temperature(TG5%)of FeS_(2)-Au is 72.2℃ higher than that of pristine FeS_(2).At a discharge temperature of 500℃,a current density of 200 mA·cm^(-2) and a cutoff voltage of 1.4 V,FeS_(2)-Au_(4)demonstrates superior specific capacity and high specific energy compared to FeS_(2).More precisely,the specific capacity of FeS_(2)-Au_(4)attains a value of 379 mAh·g^(-1),with a corresponding specific energy of 714 Wh·kg^(-1).In contrast,the discharge specific capacity and specific energy of FeS_(2)are lower,amounting to 348 mAh·g^(-1)and 656 Wh·kg^(-1),respectively.This study offers a novel approach to enhancing the electrochemical performance of FeS_(2)in high-temperature molten salt electrochemical systems(thermal batteries),thereby laying a solid foundation for its potential practical application.展开更多
Although manganese-based oxide is regarded as a promising cathode material for zincion hybrid supercapacitors(ZHSCs),its practical application is hindered by slow zinc ion diffusion and the instability of MnO_(2).To o...Although manganese-based oxide is regarded as a promising cathode material for zincion hybrid supercapacitors(ZHSCs),its practical application is hindered by slow zinc ion diffusion and the instability of MnO_(2).To overcome this obstacle,a δ-MnO_(2)/MXene heterostructure was created using a simple one-step process under gentle condition.The ZHSC was assembled using this heterostructure as the cathode,activated carbon(AC)as the anode and 2 mol·L−1 ZnSO_(4) as the electrolyte.The resultingδ-MnO_(2)/MXene//ZnSO4//AC ZHSC shows a maximum specific capacitance of 97.4 F·g^(−1) and an energy density of 32.27 Wh·kg^(−1) at the best cathode-to-anode mass ratio.Ex situ characterizations reveal the reversible energy storage mechanism combing Zn^(2+)insertion/extraction in the cathode,ion adsorption and desorption on the anode surface,and partial reversible formation and dissolution of Zn_(4)SO_(4)(OH)_(6)·5H_(2)O(ZHS)components on both electrodes.Adding of Mn^(2+)to the electrolyte reduced Mn dissolution,improving the ZHSC’s specific capacitance and energy density to 140.4 F·g^(−1) and 49.36 Wh·kg^(−1),respectively,while also enhancing its rate performance and cyclability.The improved electrochemical reaction kinetics was verified through various tests.The results suggest that the δ-MnO_(2)/MXene heterostructure has great potential as a high-performance cathode material for ZHSCs.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
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
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
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
To investigate the mechanism by which ZrO_(2)modification affects the electrochemical performance of the NaNi_(1/3)Fe_(1/3)Mn_(1/3)O_(2)(NFM)cathode material for sodium-ion batteries,ZrO_(2)-coated NFM(ZrO_(2)@NFM)was...To investigate the mechanism by which ZrO_(2)modification affects the electrochemical performance of the NaNi_(1/3)Fe_(1/3)Mn_(1/3)O_(2)(NFM)cathode material for sodium-ion batteries,ZrO_(2)-coated NFM(ZrO_(2)@NFM)was prepared via high-temperature calcination.XRD refinement results revealed that ZrO_(2)modification increased the Na-layer spacing in the NFM material.XPS analysis results demonstrated that ZrO_(2)modification adjusted the Mn^(3+)/Mn^(4+)ratio in NFM by reducing the Mn^(3+)content.Electrochemical test results revealed that,compared to NFM,ZrO_(2)@NFM exhibited superior rate capability and cycling stability.It also exhibited significantly enhanced Na^(+)diffusion coefficients and reduced interfacial charge transfer resistance.The ZrO_(2)coating increased Na-layer spacing,reduced electrochemical polarization,and inhibited side reactions.In summary,the synergistic effect of component regulation and surface engineering through ZrO_(2)coating improved Na^(+)diffusion kinetics and enhanced cycling stability.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
Spinel LiNi_(0.5)Mn_(1.5)O_(4)(LNMO)cathode draws significant attention in the field of energy storage due to its unique voltage plateau.To further enhance the long-term electrochemical stability of LNMO,the LNMO cath...Spinel LiNi_(0.5)Mn_(1.5)O_(4)(LNMO)cathode draws significant attention in the field of energy storage due to its unique voltage plateau.To further enhance the long-term electrochemical stability of LNMO,the LNMO cathode covered with an ultrathin ZrO_(2)layer was prepared through atomic layer deposition(ALD).It is found that the LNMO cathode deposited with 20 layers of ZrO_(2)(LNMOZ20)exhibits the best electrochemical performance,achieving a high discharge capacity of 117.1 mA·h/g,with a capacity retention of 87.4%after 600 cycles at a current density of 1C.Furthermore,even at higher current densities of 5C and 10C,the LNMOZ20 electrode still demonstrates excellent stability with discharge capacities reaching 111.7 and 103.6 mA·h/g,and capacity retentions maintaining at 81.0%and 101.4%after 2000 cycles,respectively.This study highlights that the incorporation of an ultrathin ZrO_(2)layer by ALD is an effective strategy for enhancing the long-term cycling stability of LNMO cathodes.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
All-solid-state Li-S batteries(ASSLSBs)are more attractive owing to their achievable superior energy density at a reasonable cost and the solid electrolyte(SE)utilization mitigating the widely recognized polysulfide s...All-solid-state Li-S batteries(ASSLSBs)are more attractive owing to their achievable superior energy density at a reasonable cost and the solid electrolyte(SE)utilization mitigating the widely recognized polysulfide shuttle problem.While the volume expansion(~80%)that occurs during the initial transformation of sulfur to lithium sulfide induces mechanical stress,this can be avoided by using Li_(2)S as a cathode,which also permits the anode-free cell design.However,the high oxidation energy barrier of Li_(2)S cathode during the charging step limits its application in commercial devices.Redox mediators have been extensively used to reduce the oxidation energy barrier of Li_(2)S to the sulfur conversation and boost the reversible kinetics of the conversion reaction.In this review,we have summarized the available redox mediators for Li_(2)S cathode in ASSLSBs and its working mechanism.Moreover,we have proposed novel strategies and guidelines for designing effective redox mediators to boost the reversible conversion reaction.展开更多
Enhancing the specific capacity of P2-type layered oxide cathodes via elevating the upper operation voltage would inevitably deteriorate electrochemical properties owing to the irreversible anionic redox reaction at h...Enhancing the specific capacity of P2-type layered oxide cathodes via elevating the upper operation voltage would inevitably deteriorate electrochemical properties owing to the irreversible anionic redox reaction at high voltage.In this work,the strategy of the electron donor was utilized to address this issue.Remarkably,the earth-abundant P2-layered cathode Na_(2/3)Al_(1/6)Fe_(1/6)Mn_(2/3)O_(2)with the presence of K_(2)S renders superior rate capability(187.4 and 79.5 mA h g^(-1)at 20 and 1000 mA g^(-1))and cycling stability(a capacity retention of 85.6% over 300 cycles at 1000 mA g^(-1))within the voltage region of 2-4.4 V Na^(+)/Na.Furthermore,excellent electrochemical performance is also demonstrated in the full cell.Detailed structural analysis of as-proposed composite cathode illustrates that even at 4.4 V irreversible phase transition can be avoided as well as a cell volume variation of only 0.88%,which are attributed to the enhanced performance compared with the control group.Meanwhile,further investigation of charge compensation reveals the crucial role of sulfur ions in actively control of reversible redox reaction of oxygen species in the lattice structure.This work inspires a new strategy to enhance the structural stability of layered sodium ion cathode materials at high voltages.展开更多
The development of affordable,high-efficiency sodium-ion batteries is primarily dependent on the advancement of cathode materials.These materials need to exhibit a high cell voltage,significant storage capacity,and qu...The development of affordable,high-efficiency sodium-ion batteries is primarily dependent on the advancement of cathode materials.These materials need to exhibit a high cell voltage,significant storage capacity,and quick diffusion of sodium ions to fulfill the requirements for efficient and ecofriendly energy storage systems.In this vein,density functional theory(DFT)calculation has become instrumental in advancing the study of battery materials.This study presents a firstprinciples investigation of P2-type Na_(x)NiO_(2)and Na_(x)Ni_(0.75)M_(0.25)O_(2)(M=Cu,Fe,Mn)cathode materials for sodium-ion batteries(SIBs),focusing on Na content variation and its impact on the battery performance.For NaNiO_(2),we replaced part of the expensive Ni element with lower-cost Cu,Fe,and Mn in hopes of reducing costs and improving material performance.By employing density functional theory(DFT),we explore the relationship between lattice constants,cell volume,enthalpy of formation,and cell voltage,and how these factors influence sodium ion insertion/extraction.We provide insights into the diffusion paths and activation energies for Na ions,and assess the influence of transition metal(TM)substitution on the structural stability and electrochemical properties of the materials.Additionally,the study delves into the electronic structure,highlighting how Cu and Fe integration refines the band gap of the spin-down bands.The findings reveal that certain transition metal substitutions can enhance performance,offering a pathway to optimize sodium-ion battery electrode materials.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
文摘The effects of FeS 2 on the discharge characteristics of Li B alloy/FeS 2 thermal battery had been studied. Results showed that 2.5%(mass fraction)Li 2O would be needed to rule out the voltage pulse in the first part of discharge curves for the FeS 2 powder of small particle size (<44 μm). After thermal decomposition, the FeS 2 had transformed to Fe (1- x ) S where x =0.024～0.066. The deficiency of the cathode FeS 2 would make discharge voltage decrease 0.4 V. In the discharge test at high temperature (600 ℃), the discharge voltage decreased fast with the acceleration of the thermal decomposition of FeS 2.
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 Central South University Innovation-Driven Research Programme(No.2023CXQD009).
文摘Iron disulfide(FeS_(2))has been widely used in thermal batteries because of its high theoretical specific capacity and voltage plateau.However,low thermal decomposition temperature,poor conductivity and inferior actual specific capacity limit its wide applications.Herein,we report a gold-doped FeS_(2)(FeS_(2)-Au),which not only reduces the band gap of the FeS_(2)crystals but also enriches the electron transport path of FeS_(2)by the formation of Au nanoparticles.First-principles calculation shows that the diffusion energy barrier of lithium-ion is reduced after the Au-doped FeS_(2).In addition,Au increases the electron cloud density around sulfur atoms,which helps to enhance the stability of Fe-S covalent bonds and thus results in better thermal stability of FeS_(2).When the Au content is 130μg·g^(-1)(FeS_(2)-Au_(4)),the thermal decomposition temperature(TG5%)of FeS_(2)-Au is 72.2℃ higher than that of pristine FeS_(2).At a discharge temperature of 500℃,a current density of 200 mA·cm^(-2) and a cutoff voltage of 1.4 V,FeS_(2)-Au_(4)demonstrates superior specific capacity and high specific energy compared to FeS_(2).More precisely,the specific capacity of FeS_(2)-Au_(4)attains a value of 379 mAh·g^(-1),with a corresponding specific energy of 714 Wh·kg^(-1).In contrast,the discharge specific capacity and specific energy of FeS_(2)are lower,amounting to 348 mAh·g^(-1)and 656 Wh·kg^(-1),respectively.This study offers a novel approach to enhancing the electrochemical performance of FeS_(2)in high-temperature molten salt electrochemical systems(thermal batteries),thereby laying a solid foundation for its potential practical application.
基金supported by Natural Science Foundation of Ningxia Province,China(No.2023AAC05047)Special Project for the Central-Guided Local Science and Technology Development(No.2024FRD05062)+1 种基金Graduate Student Innovation Project of North Minzu University(No.YCX24102)Ningxia Science and Technology Innovation Team for Key Materials and Devices in High-Performance Secondary Batteries(No.2024CXTD003).
文摘Although manganese-based oxide is regarded as a promising cathode material for zincion hybrid supercapacitors(ZHSCs),its practical application is hindered by slow zinc ion diffusion and the instability of MnO_(2).To overcome this obstacle,a δ-MnO_(2)/MXene heterostructure was created using a simple one-step process under gentle condition.The ZHSC was assembled using this heterostructure as the cathode,activated carbon(AC)as the anode and 2 mol·L−1 ZnSO_(4) as the electrolyte.The resultingδ-MnO_(2)/MXene//ZnSO4//AC ZHSC shows a maximum specific capacitance of 97.4 F·g^(−1) and an energy density of 32.27 Wh·kg^(−1) at the best cathode-to-anode mass ratio.Ex situ characterizations reveal the reversible energy storage mechanism combing Zn^(2+)insertion/extraction in the cathode,ion adsorption and desorption on the anode surface,and partial reversible formation and dissolution of Zn_(4)SO_(4)(OH)_(6)·5H_(2)O(ZHS)components on both electrodes.Adding of Mn^(2+)to the electrolyte reduced Mn dissolution,improving the ZHSC’s specific capacitance and energy density to 140.4 F·g^(−1) and 49.36 Wh·kg^(−1),respectively,while also enhancing its rate performance and cyclability.The improved electrochemical reaction kinetics was verified through various tests.The results suggest that the δ-MnO_(2)/MXene heterostructure has great potential as a high-performance cathode material for ZHSCs.
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 Central South University Innovation-Driven Research Programme,China(No.2023CXQD053)the National Natural Science Foundation of China(No.52274310)financial support from the Government of Chongzuo,Guangxi Zhuang Autonomous Region,China(No.FA20210713).
文摘To investigate the mechanism by which ZrO_(2)modification affects the electrochemical performance of the NaNi_(1/3)Fe_(1/3)Mn_(1/3)O_(2)(NFM)cathode material for sodium-ion batteries,ZrO_(2)-coated NFM(ZrO_(2)@NFM)was prepared via high-temperature calcination.XRD refinement results revealed that ZrO_(2)modification increased the Na-layer spacing in the NFM material.XPS analysis results demonstrated that ZrO_(2)modification adjusted the Mn^(3+)/Mn^(4+)ratio in NFM by reducing the Mn^(3+)content.Electrochemical test results revealed that,compared to NFM,ZrO_(2)@NFM exhibited superior rate capability and cycling stability.It also exhibited significantly enhanced Na^(+)diffusion coefficients and reduced interfacial charge transfer resistance.The ZrO_(2)coating increased Na-layer spacing,reduced electrochemical polarization,and inhibited side reactions.In summary,the synergistic effect of component regulation and surface engineering through ZrO_(2)coating improved Na^(+)diffusion kinetics and enhanced cycling stability.
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 National Natural Science Foundation of China(Nos.51931006,U22A20118).
文摘Spinel LiNi_(0.5)Mn_(1.5)O_(4)(LNMO)cathode draws significant attention in the field of energy storage due to its unique voltage plateau.To further enhance the long-term electrochemical stability of LNMO,the LNMO cathode covered with an ultrathin ZrO_(2)layer was prepared through atomic layer deposition(ALD).It is found that the LNMO cathode deposited with 20 layers of ZrO_(2)(LNMOZ20)exhibits the best electrochemical performance,achieving a high discharge capacity of 117.1 mA·h/g,with a capacity retention of 87.4%after 600 cycles at a current density of 1C.Furthermore,even at higher current densities of 5C and 10C,the LNMOZ20 electrode still demonstrates excellent stability with discharge capacities reaching 111.7 and 103.6 mA·h/g,and capacity retentions maintaining at 81.0%and 101.4%after 2000 cycles,respectively.This study highlights that the incorporation of an ultrathin ZrO_(2)layer by ALD is an effective strategy for enhancing the long-term cycling stability of LNMO cathodes.
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supported by the“Regional Innovation Strategy(RIS)”through the National Research Foundation of Korea(NRF),funded by the Ministry of Education(MOE)(2021RIS-003),South Koreasupported by the National Research Foundation of Korea(NRF)grant funded by the Korea government(MSIT)(No.RS-2023-00241916),South Korea+4 种基金supported by the National Research Foundation of Korea(NRF)grant funded by the Korea government(MSIT)(IRIS RS-2024-00352303),South Koreathe results of a study on the“Leaders in Industry-university Cooperation 3.0”project,supported by the Ministry of Education and National Research Foundation of Korea,South Koreasupported by the Basic Science Research Program through the National Research Foundation of Korea(NRF),funded by the Ministry of Education(2020R1A6A03038697),South Koreasupported by Learning&Academic research institution for Master’s PhD students,and Postdocs(LAMP)Program of the National Research Foundation of Korea(NRF)grant funded by the Ministry of Education(No.RS-2023-00301974),South Koreasupported by the Technology Innovation Program(RS-2024-00432013)funded By the Ministry of Trade,Industry&Energy(MOTIE,South Korea)。
文摘All-solid-state Li-S batteries(ASSLSBs)are more attractive owing to their achievable superior energy density at a reasonable cost and the solid electrolyte(SE)utilization mitigating the widely recognized polysulfide shuttle problem.While the volume expansion(~80%)that occurs during the initial transformation of sulfur to lithium sulfide induces mechanical stress,this can be avoided by using Li_(2)S as a cathode,which also permits the anode-free cell design.However,the high oxidation energy barrier of Li_(2)S cathode during the charging step limits its application in commercial devices.Redox mediators have been extensively used to reduce the oxidation energy barrier of Li_(2)S to the sulfur conversation and boost the reversible kinetics of the conversion reaction.In this review,we have summarized the available redox mediators for Li_(2)S cathode in ASSLSBs and its working mechanism.Moreover,we have proposed novel strategies and guidelines for designing effective redox mediators to boost the reversible conversion reaction.
基金funding support from the Beijing Natural Science Foundation(2252055)National Natural Science Foundation of China(52072033)BIT Research and Innovation Promoting Project(2024YCXY040,GIIP2023-34)。
文摘Enhancing the specific capacity of P2-type layered oxide cathodes via elevating the upper operation voltage would inevitably deteriorate electrochemical properties owing to the irreversible anionic redox reaction at high voltage.In this work,the strategy of the electron donor was utilized to address this issue.Remarkably,the earth-abundant P2-layered cathode Na_(2/3)Al_(1/6)Fe_(1/6)Mn_(2/3)O_(2)with the presence of K_(2)S renders superior rate capability(187.4 and 79.5 mA h g^(-1)at 20 and 1000 mA g^(-1))and cycling stability(a capacity retention of 85.6% over 300 cycles at 1000 mA g^(-1))within the voltage region of 2-4.4 V Na^(+)/Na.Furthermore,excellent electrochemical performance is also demonstrated in the full cell.Detailed structural analysis of as-proposed composite cathode illustrates that even at 4.4 V irreversible phase transition can be avoided as well as a cell volume variation of only 0.88%,which are attributed to the enhanced performance compared with the control group.Meanwhile,further investigation of charge compensation reveals the crucial role of sulfur ions in actively control of reversible redox reaction of oxygen species in the lattice structure.This work inspires a new strategy to enhance the structural stability of layered sodium ion cathode materials at high voltages.
基金the financial support from the National Natural Science Foundation of China(No.52072379)the Recruitment Program of Global Experts,and the Fundamental Research Funds for the Central Universities(WK2060000016)。
文摘The development of affordable,high-efficiency sodium-ion batteries is primarily dependent on the advancement of cathode materials.These materials need to exhibit a high cell voltage,significant storage capacity,and quick diffusion of sodium ions to fulfill the requirements for efficient and ecofriendly energy storage systems.In this vein,density functional theory(DFT)calculation has become instrumental in advancing the study of battery materials.This study presents a firstprinciples investigation of P2-type Na_(x)NiO_(2)and Na_(x)Ni_(0.75)M_(0.25)O_(2)(M=Cu,Fe,Mn)cathode materials for sodium-ion batteries(SIBs),focusing on Na content variation and its impact on the battery performance.For NaNiO_(2),we replaced part of the expensive Ni element with lower-cost Cu,Fe,and Mn in hopes of reducing costs and improving material performance.By employing density functional theory(DFT),we explore the relationship between lattice constants,cell volume,enthalpy of formation,and cell voltage,and how these factors influence sodium ion insertion/extraction.We provide insights into the diffusion paths and activation energies for Na ions,and assess the influence of transition metal(TM)substitution on the structural stability and electrochemical properties of the materials.Additionally,the study delves into the electronic structure,highlighting how Cu and Fe integration refines the band gap of the spin-down bands.The findings reveal that certain transition metal substitutions can enhance performance,offering a pathway to optimize sodium-ion battery electrode materials.
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.
