Layered transition metal oxides have emerged as promising cathode materials for sodium ion batteries.However,irreversible phase transitions cause structural distortion and cation rearrangement,leading to sluggish Na+d...Layered transition metal oxides have emerged as promising cathode materials for sodium ion batteries.However,irreversible phase transitions cause structural distortion and cation rearrangement,leading to sluggish Na+dynamics and rapid capacity decay.In this study,we propose a medium-entropy cathode by simultaneously introducing Fe,Mg,and Li dopants into a typical P2-type Na_(0.75)Ni_(0.25)Mn_(0.75)O_(2)cathode.The modified Na_(0.75)Ni_(0.2125)Mn_(0.6375)Fe_(0.05)Mg_(0.05)Li_(0.05)O_(2)cathode predominantly exhibits a main P2 phase(93.5%)with a minor O3 phase(6.5%).Through spectroscopy techniques and electrochemical investigations,we elucidate the redox mechanisms of Ni^(2+/3+/4+),Mn^(3+/4+),Fe^(3+/4+),and O_(2)-/O_(2)^(n-)during charging/discharging.The medium-entropy doping mitigates the detrimental P2-O_(2)phase transition at high-voltage,replacing it with a moderate and reversible structural evolution(P2-OP4),thereby enhancing structural stability.Consequently,the modified cathode exhibits a remarkable rate capacity of 108.4 mAh·g^(-1)at 10C,with a capacity retention of 99.0%after 200 cycles at 1C,82.5%after 500 cycles at 5C,and 76.7%after 600 cycles at 10C.Furthermore,it also demonstrates superior electrochemical performance at high cutoff voltage of 4.5 V and extreme temperature(55 and 0℃).This work offers solutions to critical challenges in sodium ion batteries cathode materials.展开更多
P2/O3-type Ni/Mn-based layered oxides are promising cathode materials for sodium-ion batteries(SIBs)owing to their high energy density.However,exploring effective ways to enhance the synergy between the P2 and 03 phas...P2/O3-type Ni/Mn-based layered oxides are promising cathode materials for sodium-ion batteries(SIBs)owing to their high energy density.However,exploring effective ways to enhance the synergy between the P2 and 03 phases remains a necessity.Herein,we design a P2/O3-type Na_(0.76)Ni_(0.31)Zn_(0.07)Mn_(0.50)Ti_(0.12)0_(2)(NNZMT)with high chemical/electrochemical stability by enhancing the coupling between the two phases.For the first time,a unique Na*extraction is observed from a Na-rich O3 phase by a Na-poor P2 phase and systematically investigated.This process is facilitated by Zn^(2+)/Ti^(4+)dual doping and calcination condition regulation,allowing a higher Na*content in the P2 phase with larger Na^(+)transport channels and enhancing Na transport kinetics.Because of reduced Na^(+)in the O3 phase,which increases the difficulty of H^(+)/Na^(+) exchange,the hydrostability of the O3 phase in NNZMT is considerably improved.Furthermore,Zn^(2+)/Ti^(4+)presence in NNZMT synergistically regulates oxygen redox chemistry,which effectively suppresses O_(2)/CO_(2) gas release and electrolyte decomposition,and completely inhibits phase transitions above 4.0 V.As a result,NNZMT achieves a high discharge capacity of 144.8 mA h g^(-1) with a median voltage of 3.42 V at 20 mA g^(-1) and exhibits excellent cycling performance with a capacity retention of 77.3% for 1000 cycles at 2000 mA g^(-1).This study provides an effective strategy and new insights into the design of high-performance layered-oxide cathode materials with enhanced structure/interface stability forSIBs.展开更多
Nanostructure K2NiF4 type oxides La2-xKxCuO4 complex oxides were prepared using the Sol-Gel method, characterized by X-Ray Diffraction （XRD）, Fourier Transform Infrared （FT-IR）, and Scanning Electron Microscopy （...Nanostructure K2NiF4 type oxides La2-xKxCuO4 complex oxides were prepared using the Sol-Gel method, characterized by X-Ray Diffraction （XRD）, Fourier Transform Infrared （FT-IR）, and Scanning Electron Microscopy （SEM）. The catalytic activity for soot combustion was evaluated by the Temperature-Programmed Reaction （TPO） technique. The results demonstrated that the substitution quality of K^＋ for La^3＋ at the A-site would increase the catalytic activities of La2-xKxCuO4 for soot combustion greatly; the substitution quality affected the structure and catalytic activity obviously. The La1.8K0.2CuO4 complex oxides with tetrahedral structures had the best catalytic activity for soot combustion, and the ignition temperature of soot combustion was lowered from 490 to 320 ℃.展开更多
The development on capacity and structure issues of P2-type cathode has so far focused on ion-doping/substitution strategy.In a recent report published in Journal of the American Chemical Society,Hu and colleagues dem...The development on capacity and structure issues of P2-type cathode has so far focused on ion-doping/substitution strategy.In a recent report published in Journal of the American Chemical Society,Hu and colleagues demonstrated that high Na-content P2-type layered oxides exhibit higher capacities as well as great structural stability.展开更多
The K2NiF4 type oxides, La2-x KxCuO4 complex oxides with nanometric size were prepared by sol-gel method. The characters of these samples were analyzed by H2-TPR, XRD, FT-IR and SEM. The catalytic activity for soot co...The K2NiF4 type oxides, La2-x KxCuO4 complex oxides with nanometric size were prepared by sol-gel method. The characters of these samples were analyzed by H2-TPR, XRD, FT-IR and SEM. The catalytic activity for soot combustion was evaluated by temperature-programmed reaction （TPO） technique. The results demonstrate that the substitution of K^＋ for La^3＋ at A-site will increase the catalytic activities of La2-xKxCuO4 to soot combustion greatly, and the substitution quantity affects the structure and catalytic activity obviously. The La1.8 K0.2 CuO4 complex oxides with tetrahedral structure has the best catalytic activity for soot removal reaction, the ignition temperature of soot combustion is decreased from 490 to 320℃.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
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
The development of high-performance layered oxide cathodes for sodium ion batteries (SIBs) continues to facing be hindered by severe challenges to date.Herein,a single-phase P2-Na0.67Mn0.6Ni0.2Co0.1Cu0.1O2(NMNCC) comp...The development of high-performance layered oxide cathodes for sodium ion batteries (SIBs) continues to facing be hindered by severe challenges to date.Herein,a single-phase P2-Na0.67Mn0.6Ni0.2Co0.1Cu0.1O2(NMNCC) comprising multiple-layer-oriented stacked nanoflakes is designed and synthesized via a simple sol-gel method.The large lattice parameters ensure a large three-dimensional frame,which enables the diffusion of sodium ions.Owing to its optimal morphology structure modulation transition metal substitution strategy,the MNCC electrode delivers a reversible capacity of 131.3 mAh g^-1 at 0.1 C with retention of 86.7%after 200 cycles.In addition,it provides an initial capacity of 86.7 mAh g^-1,and a retention of 80.0%after 500 cycles even at a current density of up to 1 A g^-1.The stable single-phase structure and slight volume shrinkage observed after Na+extraction further delay structural degradation.High Na+mobility and low Na+diffusion resistance are also guarantee the excellent rate performance of the NMNCC electrode.Thus,we determine that the NMNCC cathode is significant in the advancement of promising novel layered oxide cathodes.展开更多
Li-rich layered oxide(LRLO)cathodes have been regarded as promising candidates for next-generation Li-ion batteries due to their exceptionally high energy density,which combines cationic and anionic redox activities.H...Li-rich layered oxide(LRLO)cathodes have been regarded as promising candidates for next-generation Li-ion batteries due to their exceptionally high energy density,which combines cationic and anionic redox activities.However,continuous voltage decay during cycling remains the primary obstacle for practical applications,which has yet to be fundamentally addressed.It is widely acknowledged that voltage decay originates from the irreversible migration of transition metal ions,which usually further exacerbates structural evolution and aggravates the irreversible oxygen redox reactions.Recently,constructing O2-type structure has been considered one of the most promising approaches for inhibiting voltage decay.In this review,the relationship between voltage decay and structural evolution is systematically elucidated.Strategies to suppress voltage decay are systematically summarized.Additionally,the design of O2-type structure and the corresponding mechanism of suppressing voltage decay are comprehensively discussed.Unfortunately,the reported O2-type LRLO cathodes still exhibit partially disordered structure with extended cycles.Herein,the factors that may cause the irreversible transition metal migrations in O2-type LRLO materials are also explored,while the perspectives and challenges for designing high-performance O2-type LRLO cathodes without voltage decay are proposed.展开更多
The anionic redox has been widely studied in layered-oxide-cathodes in attempts to achieve highenergy-density for Na-ion batteries(NIBs).It is known that an oxidation state of Mn^(4+) or Ru^(5+) is essential for the a...The anionic redox has been widely studied in layered-oxide-cathodes in attempts to achieve highenergy-density for Na-ion batteries(NIBs).It is known that an oxidation state of Mn^(4+) or Ru^(5+) is essential for the anionic reaction of O^(2-)/O~-to occur during Na^(+) de/intercalation.However,here,we report that the anionic redox can occur in Ru-based layered-oxide-cathodes before full oxidation of Ru^(4+)/Ru^(5+).Combining studies using first-principles calculation and experimental techniques reveals that further Na^(+) deintercalation from P2-Na_(0.33)[Mg_(0.33)Ru_(0.67)]O_(2) is based on anionic oxidation after 0.33 mol Na^(+) deintercalation from P2-Na_(0.67)[Mg_(0.33)Ru_(0.67)]O_(2) with cationic oxidation of Ru^(4+)/Ru^(4.5+).Especially,it is revealed that the only oxygen neighboring 2Mg/1 Ru can participate in the anionic redox during Na^(+) de/intercalation,which implies that the Na-O-Mg arrangement in the P2-Na_(0.33)[M9_(0.33)Ru_(0.67)]O_(2) structure can dramatically lower the thermodynamic stability of the anionic redox than that of cationic redox.Through the O anionic and Ru cationic reaction,P2-Na_(0.67)[Mg_(0.33)Ru_(0.67)]O_(2) exhibits not only a large specific capacity of~172 mA h g^(-1) but also excellent power-capability via facile Na^(+) diffusion and reversible structural change during charge/discharge.These findings suggest a novel strategy that can increase the activity of anionic redox by modulating the local environment around oxygen to develop high-energy-density cathode materials for NIBs.展开更多
Due to the sodium abundance and availability,sodium-ion batteries(SIBs)have the potential to meet the worldwide growing demand of electrical energy storage.P2-type sodium transition-metal layer oxides with a high ener...Due to the sodium abundance and availability,sodium-ion batteries(SIBs)have the potential to meet the worldwide growing demand of electrical energy storage.P2-type sodium transition-metal layer oxides with a high energy density are considered as the most promising cathode materials for SIBs.We present here a detailed study of the enhanced rate capability and cyclic stability of the Ti-doped Na_(0.67)Ni_(0.33)Mn_(0.67)O_(2)cathode material.The combined analysis of ex-situ X-ray absorption fine structure(XAFS)spectroscopy,aberration-corrected high resolution transmission electron microscopy(AB-HRTEM)and X-ray diffraction(XRD)show that the strong Ti–O bond in the transition metal layers stabilizes the local structure,destroy the Na+-vacancy ordering and arrest the irreversible multiphase transformation that occurs during the intercalation/deintercalation process.Actually,Na_(0.67)Ni_(0.33)Mn_(0.52)Ti_(0.15)O_(2)exhibits a reversible capacity of 89.6 mA h g^(-1)even at 5 C,an excellent cyclability with 88.78%capacity retention after 200 cycles at 0.5 C.This study provides a better understanding in optimization of the design of high-energy cathode materials based on titanium doped layered oxides for SIBs.展开更多
Traditional O3-type Li-rich layered materials are attractive with ultra-high specific capacities,but suffering from inherent problems of voltage hysteresis and poor cycle performance.As an alternative,O2-type material...Traditional O3-type Li-rich layered materials are attractive with ultra-high specific capacities,but suffering from inherent problems of voltage hysteresis and poor cycle performance.As an alternative,O2-type materials show the potential to improve the oxygen redox reversibility and structural stability.However,their structure-performance relationship is still unclear.Here,we investigate the correlation between the Li component and dynamic chemical reversibility of O2-type Li-rich materials.By exploring the formation mechanism of a series of materials prepared by Na/Li exchange,we reveal that insufficient Li leads to an incomplete replacement,and the residual Na in the Li-layer would hinder the fast diffusion of Li^(+).Moreover,excessive Li induces the extraction of interlayer Li during the melting chemical reaction stage,resulting in a reduction in the valence of Mn,which leads to a severe Jahn-Teller effect.Structural detection confirms that the regulation of Li can improve the cycle stability of Li-rich materials and suppress the trend of voltage fading.The reversible phase evolution observed in in-situ X-ray diffraction confirms the excellent structural stability of the optimized material,which is conducive to capacity retention.This work highlights the significance of modulating dynamic electrochemical performance through the intrinsic structure.展开更多
Highly active and low-cost catalytic electrodes for urea oxidation reaction(UOR)are always crucial for exploration of urea fuel cells.Herein,novel york-shell-structural Ni_(2)P/C na nosphere hybrids(Ni_(2)P/C-YS)are r...Highly active and low-cost catalytic electrodes for urea oxidation reaction(UOR)are always crucial for exploration of urea fuel cells.Herein,novel york-shell-structural Ni_(2)P/C na nosphere hybrids(Ni_(2)P/C-YS)are rationally constructed via a hydrothermal method and subsequent phosphidation treatment under different temperature ranging from 250℃to 450℃for UOR applications.In the in-situ constructed hollow york-shell structure,the coupling of conductive carbon materials and active Ni_(2)P allows numerous interfaces facilitating the electron transfer and thereby accelerating the catalytic kinetics.The results demonstrate that Ni_(2)P/C-YS-350 nanocomposite can boost the UOR process with a low potential of 1.366 V vs.RHE at a current density of 50 mA/cm^(2) in alkaline electrolyte and afford the superior durability with negligible potential decay after 23 h.This study presents that the carbon coated Ni_(2)P hybrid with the optimized crystallinities and hollow york-shell configurations can be a promising candidate for application in urea fuel cells.展开更多
A series of Na-W-Mn-Zr/SiO2 catalysts promoted by different contents of S or/and P were prepared and their catalytic performance for oxidative coupling of methane was investigated to clarify the effect of S and P on t...A series of Na-W-Mn-Zr/SiO2 catalysts promoted by different contents of S or/and P were prepared and their catalytic performance for oxidative coupling of methane was investigated to clarify the effect of S and P on the Na-W-Mn-Zr/SiO2 catalyst. The catalysts were characterized by X-ray diffraction （XRD） and X-ray photoelectron spectroscopy （XPS）. From the characterization results, it is found that the addition of S and P to the Na-W-Mn-ZffSiO2 catalyst helps the formation of active phases, such as α-cristobalite, Na2WO4, ZrO2, and Na2SO4. Moreover, the addition of S and P increases the concentration of surface-active oxygen species by improving the migration of active components from the bulk phase to the surface of the catalyst. According to the activity test, impressive methane conversion and C2 hydrocarbons yield were obtained at a low temperature of 1023 K over the six-component Na-W-Mn-Zr-S-P/SiO2 catalyst, which contained 2 wt% S and 0.4 wt% P simultaneously. The deactivation of Na-W-Mn-Zr-S-P/SiO2 was due to the loss of surface active components.展开更多
The effect of Na-excess content in the precursor on the structural and electrochemical performances of sodium nickel manganese oxide(NNMO)prepared by sol-gel and electrospinning methods is investigated in this paper.X...The effect of Na-excess content in the precursor on the structural and electrochemical performances of sodium nickel manganese oxide(NNMO)prepared by sol-gel and electrospinning methods is investigated in this paper.X-ray diffraction results of the prepared NNMO without adding Na-excess content indicate sodium loss,while the mixed phase of P2/O′3-type layered NNMO presented after adding Na-excess content.Compared with the sol-gel method,the secondary phase of NiO is more suppressed by using the electrospinning method,which is further confirmed by field emission scanning electron microscope images.N_(2) adsorption-desorption isotherms show no remarkably difference in specific surface areas between different preparation methods and Na-excess contents.The analysis of X-ray absorption near edge structure indicates that the oxidation states of Ni and Mn are+2 and+4,respectively.For the electrochemical properties,superior electrochemical performance is observed in the NNMO electrode with a low Na-excess content of 5wt%.The highest specific capacitance is 36.07 F·g^(-1)at0.1 A·g^(-1)in the NNMO electrode prepared by using the sol-gel method.By contrast,the NNMO electrode prepared using the electrospinning method with decreased Na-excess content shows excellent cycling stability of 100%after charge-discharge measurements for 300 cycles.Therefore,controlling the Na excess in the precursor together with the preparation method is important for improving the electrochemical performance of Na-based electrode materials in supercapacitors.展开更多
Na-ion cathode materials with a fast charge and discharge behavior are needed to develop future high energy sodium-ion batteries(SIBs).However,inevitably complicated phase transitions and sluggish kinet ics during ins...Na-ion cathode materials with a fast charge and discharge behavior are needed to develop future high energy sodium-ion batteries(SIBs).However,inevitably complicated phase transitions and sluggish kinet ics during insertion and removal of Na+in P_(2)-type layered transition metal oxides generate structura instability and severe capacity decay.To get rid of such a dilemma,we report a structural optimization strategy to promote P2-type layered transition metal oxides with more(010)active planes as an efficien cathode for SIBs.As a result,as-prepared hexagonal-prism P2-type layered Na_(0.71)Ni_(0.16)Li_(0.09)Co_(0.16)Mn0.6O_(2)cathode with more(010)active planes delivers a reversible capacity of 120.1 mAh/g at 0.1 C,impressive rate capability of 52.7 m Ah/g at 10 C,and long-term cycling stability(capacity retention of 95.6%ove200 cycles).The outstanding electrochemical performance benefited from the unique hexagonal-prism with more(010)active facets,which can effectively shorten the diffusion distances of Na+,increase the Na-ion migration dynamics and nanostructural stability during cycling verified by morphology character ization,Rietveld refinement,GITT,density functional theory calculations and operando XRD.展开更多
The widespread interest in layered P2-type Mn-based cathode materials for sodium-ion batteries(SIBs)stems from their cost-effectiveness and abundant resources.However,the inferior cycle stability and mediocre rate per...The widespread interest in layered P2-type Mn-based cathode materials for sodium-ion batteries(SIBs)stems from their cost-effectiveness and abundant resources.However,the inferior cycle stability and mediocre rate performance impede their further development in practical applications.Herein,we devised a wet chemical precipitation method to deposit an amorphous aluminum phosphate(AlPO_(4),denoted as AP)protective layer onto the surface of P2-type Na_(0.55)Ni_(0.1)Co_(0.7)Mn_(0.8)O_(2)(NCM@AP).The resulting NCM@5AP electrode,with a 5 wt%coating,exhibits extended cycle life(capacity retention of78.4%after 200 cycles at 100 mA g^(-1))and superior rate performance(98 mA h g^(-1)at 500 mA g^(-1))compared to pristine NCM.Moreover,our investigation provides comprehensive insights into the phase stability and active Na^(+)ion kinetics in the NCM@5AP composite electrode,shedding light on the underlying mechanisms responsible for the enhanced performance observed in the coated electrode.展开更多
P2-type layered oxides have been considered as promising cathode materials for Na-ion batteries,but the capac-ity decay resulting from the Na+/vacancy ordering and phase transformation limits their future large-scale ...P2-type layered oxides have been considered as promising cathode materials for Na-ion batteries,but the capac-ity decay resulting from the Na+/vacancy ordering and phase transformation limits their future large-scale applica-tions.Herein,the impact of Li-doping in different layers on the structure and electrochemical performance of P2-type Na_(0.7)Ni_(0.35)Mn_(0.65)O_(2) is investigated.It can be found that Li ions successfully enter both the Na and transition metal layers.The strategy of Li-doping can improve the cycling stability and rate capability of P2-type layered oxides,which promotes the development of high-performance Na-ion batteries.展开更多
The substitution of elements has attracted great interest to enhance the electrochemical properties of sodium-ion batteries(SIBs).Herein,the P2-Na0.67Co0.35Ti0.20Mn0.45-xLaxO2 electrode samples were prepared via a sol...The substitution of elements has attracted great interest to enhance the electrochemical properties of sodium-ion batteries(SIBs).Herein,the P2-Na0.67Co0.35Ti0.20Mn0.45-xLaxO2 electrode samples were prepared via a solid-state route.The effect of La3+substitution was researched as high-rate SIBs cathode.The Na0.67Co0.35Ti0.20Mn0.44La0.01O2 exhibits a superior initial specific capacity of 162.7 and 125.9 mA h/g after50 cycles at 0.1 C rate,and the initial specific discharge capacity of 115.2 mA h/g with 60.6%capacity retention after 100 cycles at 1 C In addition,the Na0.67Co0.35Ti0.20Mn0.44La0.01O2 sample shows an excellent rate capacity of 91.9 and 60.4 mA·h/g with 46.9%and 50.9%capacity retentions even at 8 C and 10 C rate after100 cycles,respectively.The promising La-substituted P2-type Na0.67Co0.35Ti0.20Mn0.45-xLaxO2 material provides a new strategy for designing high-rate performance of SIBs.展开更多
基金supported by the National Natural Science Foundation of China(No.21805018)by Sichuan Science and Technology Program(Nos.2022ZHCG0018,2023NSFSC0117 and 2023ZHCG0060)Yibin Science and Technology Program(No.2022JB005)and China Postdoctoral Science Foundation(No.2022M722704).
文摘Layered transition metal oxides have emerged as promising cathode materials for sodium ion batteries.However,irreversible phase transitions cause structural distortion and cation rearrangement,leading to sluggish Na+dynamics and rapid capacity decay.In this study,we propose a medium-entropy cathode by simultaneously introducing Fe,Mg,and Li dopants into a typical P2-type Na_(0.75)Ni_(0.25)Mn_(0.75)O_(2)cathode.The modified Na_(0.75)Ni_(0.2125)Mn_(0.6375)Fe_(0.05)Mg_(0.05)Li_(0.05)O_(2)cathode predominantly exhibits a main P2 phase(93.5%)with a minor O3 phase(6.5%).Through spectroscopy techniques and electrochemical investigations,we elucidate the redox mechanisms of Ni^(2+/3+/4+),Mn^(3+/4+),Fe^(3+/4+),and O_(2)-/O_(2)^(n-)during charging/discharging.The medium-entropy doping mitigates the detrimental P2-O_(2)phase transition at high-voltage,replacing it with a moderate and reversible structural evolution(P2-OP4),thereby enhancing structural stability.Consequently,the modified cathode exhibits a remarkable rate capacity of 108.4 mAh·g^(-1)at 10C,with a capacity retention of 99.0%after 200 cycles at 1C,82.5%after 500 cycles at 5C,and 76.7%after 600 cycles at 10C.Furthermore,it also demonstrates superior electrochemical performance at high cutoff voltage of 4.5 V and extreme temperature(55 and 0℃).This work offers solutions to critical challenges in sodium ion batteries cathode materials.
基金supported by the National Natural Science Foundation of China (22169002)the Chongzuo Key Research and Development Program of China (20220603)the Counterpart Aid Project for Discipline Construction from Guangxi University(2023M02)
文摘P2/O3-type Ni/Mn-based layered oxides are promising cathode materials for sodium-ion batteries(SIBs)owing to their high energy density.However,exploring effective ways to enhance the synergy between the P2 and 03 phases remains a necessity.Herein,we design a P2/O3-type Na_(0.76)Ni_(0.31)Zn_(0.07)Mn_(0.50)Ti_(0.12)0_(2)(NNZMT)with high chemical/electrochemical stability by enhancing the coupling between the two phases.For the first time,a unique Na*extraction is observed from a Na-rich O3 phase by a Na-poor P2 phase and systematically investigated.This process is facilitated by Zn^(2+)/Ti^(4+)dual doping and calcination condition regulation,allowing a higher Na*content in the P2 phase with larger Na^(+)transport channels and enhancing Na transport kinetics.Because of reduced Na^(+)in the O3 phase,which increases the difficulty of H^(+)/Na^(+) exchange,the hydrostability of the O3 phase in NNZMT is considerably improved.Furthermore,Zn^(2+)/Ti^(4+)presence in NNZMT synergistically regulates oxygen redox chemistry,which effectively suppresses O_(2)/CO_(2) gas release and electrolyte decomposition,and completely inhibits phase transitions above 4.0 V.As a result,NNZMT achieves a high discharge capacity of 144.8 mA h g^(-1) with a median voltage of 3.42 V at 20 mA g^(-1) and exhibits excellent cycling performance with a capacity retention of 77.3% for 1000 cycles at 2000 mA g^(-1).This study provides an effective strategy and new insights into the design of high-performance layered-oxide cathode materials with enhanced structure/interface stability forSIBs.
基金Beijing Municipal Education Committee Program (KM200710017006)
文摘Nanostructure K2NiF4 type oxides La2-xKxCuO4 complex oxides were prepared using the Sol-Gel method, characterized by X-Ray Diffraction （XRD）, Fourier Transform Infrared （FT-IR）, and Scanning Electron Microscopy （SEM）. The catalytic activity for soot combustion was evaluated by the Temperature-Programmed Reaction （TPO） technique. The results demonstrated that the substitution quality of K^＋ for La^3＋ at the A-site would increase the catalytic activities of La2-xKxCuO4 for soot combustion greatly; the substitution quality affected the structure and catalytic activity obviously. The La1.8K0.2CuO4 complex oxides with tetrahedral structures had the best catalytic activity for soot combustion, and the ignition temperature of soot combustion was lowered from 490 to 320 ℃.
文摘The development on capacity and structure issues of P2-type cathode has so far focused on ion-doping/substitution strategy.In a recent report published in Journal of the American Chemical Society,Hu and colleagues demonstrated that high Na-content P2-type layered oxides exhibit higher capacities as well as great structural stability.
文摘The K2NiF4 type oxides, La2-x KxCuO4 complex oxides with nanometric size were prepared by sol-gel method. The characters of these samples were analyzed by H2-TPR, XRD, FT-IR and SEM. The catalytic activity for soot combustion was evaluated by temperature-programmed reaction （TPO） technique. The results demonstrate that the substitution of K^＋ for La^3＋ at A-site will increase the catalytic activities of La2-xKxCuO4 to soot combustion greatly, and the substitution quantity affects the structure and catalytic activity obviously. The La1.8 K0.2 CuO4 complex oxides with tetrahedral structure has the best catalytic activity for soot removal reaction, the ignition temperature of soot combustion is decreased from 490 to 320℃.
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 Natural Science Foundation of China(No.21471162)the Hunan Provincial Science and Technology Plan Project(No.2017TP1001)Postgraduate Innovation project(No.502211822)。
文摘The development of high-performance layered oxide cathodes for sodium ion batteries (SIBs) continues to facing be hindered by severe challenges to date.Herein,a single-phase P2-Na0.67Mn0.6Ni0.2Co0.1Cu0.1O2(NMNCC) comprising multiple-layer-oriented stacked nanoflakes is designed and synthesized via a simple sol-gel method.The large lattice parameters ensure a large three-dimensional frame,which enables the diffusion of sodium ions.Owing to its optimal morphology structure modulation transition metal substitution strategy,the MNCC electrode delivers a reversible capacity of 131.3 mAh g^-1 at 0.1 C with retention of 86.7%after 200 cycles.In addition,it provides an initial capacity of 86.7 mAh g^-1,and a retention of 80.0%after 500 cycles even at a current density of up to 1 A g^-1.The stable single-phase structure and slight volume shrinkage observed after Na+extraction further delay structural degradation.High Na+mobility and low Na+diffusion resistance are also guarantee the excellent rate performance of the NMNCC electrode.Thus,we determine that the NMNCC cathode is significant in the advancement of promising novel layered oxide cathodes.
基金funded by the National Natural Science Foundation of China(Grant Nos.22279092 and 5202780089).
文摘Li-rich layered oxide(LRLO)cathodes have been regarded as promising candidates for next-generation Li-ion batteries due to their exceptionally high energy density,which combines cationic and anionic redox activities.However,continuous voltage decay during cycling remains the primary obstacle for practical applications,which has yet to be fundamentally addressed.It is widely acknowledged that voltage decay originates from the irreversible migration of transition metal ions,which usually further exacerbates structural evolution and aggravates the irreversible oxygen redox reactions.Recently,constructing O2-type structure has been considered one of the most promising approaches for inhibiting voltage decay.In this review,the relationship between voltage decay and structural evolution is systematically elucidated.Strategies to suppress voltage decay are systematically summarized.Additionally,the design of O2-type structure and the corresponding mechanism of suppressing voltage decay are comprehensively discussed.Unfortunately,the reported O2-type LRLO cathodes still exhibit partially disordered structure with extended cycles.Herein,the factors that may cause the irreversible transition metal migrations in O2-type LRLO materials are also explored,while the perspectives and challenges for designing high-performance O2-type LRLO cathodes without voltage decay are proposed.
基金supported by the National Research Foundation of Korea (NRF) grant funded by the Korean government (MSIT) (2021R1A2C1014280)supported by the “Regional Innovation Strategy (RIS)” through the National Research Foundation of Korea (NRF) funded by the Ministry of Education (MOE) (2021RIS-004)+1 种基金the Fundamental Research Program of the Korea Institute of Material Science (KIMS) (PNK9370)the calculation resources were supported by the Supercomputing Center in Korea Institute of Science and Technology Information (KISTI) (KSC-2022-CRE-0030)。
文摘The anionic redox has been widely studied in layered-oxide-cathodes in attempts to achieve highenergy-density for Na-ion batteries(NIBs).It is known that an oxidation state of Mn^(4+) or Ru^(5+) is essential for the anionic reaction of O^(2-)/O~-to occur during Na^(+) de/intercalation.However,here,we report that the anionic redox can occur in Ru-based layered-oxide-cathodes before full oxidation of Ru^(4+)/Ru^(5+).Combining studies using first-principles calculation and experimental techniques reveals that further Na^(+) deintercalation from P2-Na_(0.33)[Mg_(0.33)Ru_(0.67)]O_(2) is based on anionic oxidation after 0.33 mol Na^(+) deintercalation from P2-Na_(0.67)[Mg_(0.33)Ru_(0.67)]O_(2) with cationic oxidation of Ru^(4+)/Ru^(4.5+).Especially,it is revealed that the only oxygen neighboring 2Mg/1 Ru can participate in the anionic redox during Na^(+) de/intercalation,which implies that the Na-O-Mg arrangement in the P2-Na_(0.33)[M9_(0.33)Ru_(0.67)]O_(2) structure can dramatically lower the thermodynamic stability of the anionic redox than that of cationic redox.Through the O anionic and Ru cationic reaction,P2-Na_(0.67)[Mg_(0.33)Ru_(0.67)]O_(2) exhibits not only a large specific capacity of~172 mA h g^(-1) but also excellent power-capability via facile Na^(+) diffusion and reversible structural change during charge/discharge.These findings suggest a novel strategy that can increase the activity of anionic redox by modulating the local environment around oxygen to develop high-energy-density cathode materials for NIBs.
基金the National Natural Science Foundation of China(No.11705015,U1832147)the Science and Technology Plan Project of Suzhou(Nos.SYG201738 and SZS201710)。
文摘Due to the sodium abundance and availability,sodium-ion batteries(SIBs)have the potential to meet the worldwide growing demand of electrical energy storage.P2-type sodium transition-metal layer oxides with a high energy density are considered as the most promising cathode materials for SIBs.We present here a detailed study of the enhanced rate capability and cyclic stability of the Ti-doped Na_(0.67)Ni_(0.33)Mn_(0.67)O_(2)cathode material.The combined analysis of ex-situ X-ray absorption fine structure(XAFS)spectroscopy,aberration-corrected high resolution transmission electron microscopy(AB-HRTEM)and X-ray diffraction(XRD)show that the strong Ti–O bond in the transition metal layers stabilizes the local structure,destroy the Na+-vacancy ordering and arrest the irreversible multiphase transformation that occurs during the intercalation/deintercalation process.Actually,Na_(0.67)Ni_(0.33)Mn_(0.52)Ti_(0.15)O_(2)exhibits a reversible capacity of 89.6 mA h g^(-1)even at 5 C,an excellent cyclability with 88.78%capacity retention after 200 cycles at 0.5 C.This study provides a better understanding in optimization of the design of high-energy cathode materials based on titanium doped layered oxides for SIBs.
基金the National Natural Science Foundation of China(21673064 and 51902072)the Heilongjiang Touyan Team(HITTY-20190033)+2 种基金the Fundamental Research Funds for the Central Universities(HIT.NSRIF.2019040 and 2019041)the State Key Laboratory of Urban Water Resource and Environment(Harbin Institute of Technology)(2020 DX11)the Heilongjiang postdoctoral financial assistance(LBH-Z19055)。
文摘Traditional O3-type Li-rich layered materials are attractive with ultra-high specific capacities,but suffering from inherent problems of voltage hysteresis and poor cycle performance.As an alternative,O2-type materials show the potential to improve the oxygen redox reversibility and structural stability.However,their structure-performance relationship is still unclear.Here,we investigate the correlation between the Li component and dynamic chemical reversibility of O2-type Li-rich materials.By exploring the formation mechanism of a series of materials prepared by Na/Li exchange,we reveal that insufficient Li leads to an incomplete replacement,and the residual Na in the Li-layer would hinder the fast diffusion of Li^(+).Moreover,excessive Li induces the extraction of interlayer Li during the melting chemical reaction stage,resulting in a reduction in the valence of Mn,which leads to a severe Jahn-Teller effect.Structural detection confirms that the regulation of Li can improve the cycle stability of Li-rich materials and suppress the trend of voltage fading.The reversible phase evolution observed in in-situ X-ray diffraction confirms the excellent structural stability of the optimized material,which is conducive to capacity retention.This work highlights the significance of modulating dynamic electrochemical performance through the intrinsic structure.
基金financially supported by the National Key Research and Development Program of China(No.2017YFE0120500)the National Natural Science Foundation of China(Nos.51804223 and 51972129)+4 种基金CAS Key Laboratory of Nano-Bio Interface(No.19ZY01)the South Xinjiang Innovation and Development Program of Key Industries of Xinjiang Production and Construction Corps(No.2020DB002)the Scientific Research Foundation of Wuhan Institute of Technology(No.K201761)the Fundamental Research Funds for the Central Universities(Nos.HUST 2018KFYYXJJ051,2019KFYXMBZ076)the Hubei"Chu-Tian Young Scholar"Program。
文摘Highly active and low-cost catalytic electrodes for urea oxidation reaction(UOR)are always crucial for exploration of urea fuel cells.Herein,novel york-shell-structural Ni_(2)P/C na nosphere hybrids(Ni_(2)P/C-YS)are rationally constructed via a hydrothermal method and subsequent phosphidation treatment under different temperature ranging from 250℃to 450℃for UOR applications.In the in-situ constructed hollow york-shell structure,the coupling of conductive carbon materials and active Ni_(2)P allows numerous interfaces facilitating the electron transfer and thereby accelerating the catalytic kinetics.The results demonstrate that Ni_(2)P/C-YS-350 nanocomposite can boost the UOR process with a low potential of 1.366 V vs.RHE at a current density of 50 mA/cm^(2) in alkaline electrolyte and afford the superior durability with negligible potential decay after 23 h.This study presents that the carbon coated Ni_(2)P hybrid with the optimized crystallinities and hollow york-shell configurations can be a promising candidate for application in urea fuel cells.
基金supported by the National Natural Science Foundation of China (20676116)
文摘A series of Na-W-Mn-Zr/SiO2 catalysts promoted by different contents of S or/and P were prepared and their catalytic performance for oxidative coupling of methane was investigated to clarify the effect of S and P on the Na-W-Mn-Zr/SiO2 catalyst. The catalysts were characterized by X-ray diffraction （XRD） and X-ray photoelectron spectroscopy （XPS）. From the characterization results, it is found that the addition of S and P to the Na-W-Mn-ZffSiO2 catalyst helps the formation of active phases, such as α-cristobalite, Na2WO4, ZrO2, and Na2SO4. Moreover, the addition of S and P increases the concentration of surface-active oxygen species by improving the migration of active components from the bulk phase to the surface of the catalyst. According to the activity test, impressive methane conversion and C2 hydrocarbons yield were obtained at a low temperature of 1023 K over the six-component Na-W-Mn-Zr-S-P/SiO2 catalyst, which contained 2 wt% S and 0.4 wt% P simultaneously. The deactivation of Na-W-Mn-Zr-S-P/SiO2 was due to the loss of surface active components.
基金financially supported by (i) Suranaree University of Technology,(ii) Thailand Science Research and Innovation,and (iii) National Science,Research and Innovation Fund(project codes 90464 and 160363)。
文摘The effect of Na-excess content in the precursor on the structural and electrochemical performances of sodium nickel manganese oxide(NNMO)prepared by sol-gel and electrospinning methods is investigated in this paper.X-ray diffraction results of the prepared NNMO without adding Na-excess content indicate sodium loss,while the mixed phase of P2/O′3-type layered NNMO presented after adding Na-excess content.Compared with the sol-gel method,the secondary phase of NiO is more suppressed by using the electrospinning method,which is further confirmed by field emission scanning electron microscope images.N_(2) adsorption-desorption isotherms show no remarkably difference in specific surface areas between different preparation methods and Na-excess contents.The analysis of X-ray absorption near edge structure indicates that the oxidation states of Ni and Mn are+2 and+4,respectively.For the electrochemical properties,superior electrochemical performance is observed in the NNMO electrode with a low Na-excess content of 5wt%.The highest specific capacitance is 36.07 F·g^(-1)at0.1 A·g^(-1)in the NNMO electrode prepared by using the sol-gel method.By contrast,the NNMO electrode prepared using the electrospinning method with decreased Na-excess content shows excellent cycling stability of 100%after charge-discharge measurements for 300 cycles.Therefore,controlling the Na excess in the precursor together with the preparation method is important for improving the electrochemical performance of Na-based electrode materials in supercapacitors.
基金financially supported by the National Natural Science Foundation of China(Nos.52372188,51902090)Henan Key Research Project Plan for Higher Education Institutions(No.23A150038)+6 种基金2023 Introduction of Studying Abroad Talent Program“111”Project(No.D17007)Henan Provincial Key Scientific Research Project of Colleges and Universities(No23A150038)Key Scientific Research Project of Education Department of Henan Province(No.22A150042)the National Students’Platform for Innovation and Entrepreneurship Training Program(No.201910476010)the China Postdoctoral Science Foundation(No.2019 M652546)the Henan Province Postdoctoral StartUp Foundation(No.1901017)。
文摘Na-ion cathode materials with a fast charge and discharge behavior are needed to develop future high energy sodium-ion batteries(SIBs).However,inevitably complicated phase transitions and sluggish kinet ics during insertion and removal of Na+in P_(2)-type layered transition metal oxides generate structura instability and severe capacity decay.To get rid of such a dilemma,we report a structural optimization strategy to promote P2-type layered transition metal oxides with more(010)active planes as an efficien cathode for SIBs.As a result,as-prepared hexagonal-prism P2-type layered Na_(0.71)Ni_(0.16)Li_(0.09)Co_(0.16)Mn0.6O_(2)cathode with more(010)active planes delivers a reversible capacity of 120.1 mAh/g at 0.1 C,impressive rate capability of 52.7 m Ah/g at 10 C,and long-term cycling stability(capacity retention of 95.6%ove200 cycles).The outstanding electrochemical performance benefited from the unique hexagonal-prism with more(010)active facets,which can effectively shorten the diffusion distances of Na+,increase the Na-ion migration dynamics and nanostructural stability during cycling verified by morphology character ization,Rietveld refinement,GITT,density functional theory calculations and operando XRD.
基金financially supported by the Australian Research Council(ARC) through the Future Fellowship(FT180100705)the financial support from China Scholarship Council+3 种基金the support from UTS-HUST Key Technology Partner Seed Fundthe support from Open Project of State Key Laboratory of Advanced Special Steel,the Shanghai Key Laboratory of Advanced Ferrometallurgy,Shanghai University(SKLASS 2021-04)the Science and Technology Commission of Shanghai Municipality(22010500400)“Joint International Laboratory on Environmental and Energy Frontier Materials”and“Innovation Research Team of High–Level Local Universities in Shanghai”in Shanghai University。
文摘The widespread interest in layered P2-type Mn-based cathode materials for sodium-ion batteries(SIBs)stems from their cost-effectiveness and abundant resources.However,the inferior cycle stability and mediocre rate performance impede their further development in practical applications.Herein,we devised a wet chemical precipitation method to deposit an amorphous aluminum phosphate(AlPO_(4),denoted as AP)protective layer onto the surface of P2-type Na_(0.55)Ni_(0.1)Co_(0.7)Mn_(0.8)O_(2)(NCM@AP).The resulting NCM@5AP electrode,with a 5 wt%coating,exhibits extended cycle life(capacity retention of78.4%after 200 cycles at 100 mA g^(-1))and superior rate performance(98 mA h g^(-1)at 500 mA g^(-1))compared to pristine NCM.Moreover,our investigation provides comprehensive insights into the phase stability and active Na^(+)ion kinetics in the NCM@5AP composite electrode,shedding light on the underlying mechanisms responsible for the enhanced performance observed in the coated electrode.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.12105372 and 51991344)President's Foundation of China Institute of Atomic Energy(Grant No.16YZ202212000201)Chinese Academy of Sciences(Grant No.XDB33000000).
文摘P2-type layered oxides have been considered as promising cathode materials for Na-ion batteries,but the capac-ity decay resulting from the Na+/vacancy ordering and phase transformation limits their future large-scale applica-tions.Herein,the impact of Li-doping in different layers on the structure and electrochemical performance of P2-type Na_(0.7)Ni_(0.35)Mn_(0.65)O_(2) is investigated.It can be found that Li ions successfully enter both the Na and transition metal layers.The strategy of Li-doping can improve the cycling stability and rate capability of P2-type layered oxides,which promotes the development of high-performance Na-ion batteries.
文摘The substitution of elements has attracted great interest to enhance the electrochemical properties of sodium-ion batteries(SIBs).Herein,the P2-Na0.67Co0.35Ti0.20Mn0.45-xLaxO2 electrode samples were prepared via a solid-state route.The effect of La3+substitution was researched as high-rate SIBs cathode.The Na0.67Co0.35Ti0.20Mn0.44La0.01O2 exhibits a superior initial specific capacity of 162.7 and 125.9 mA h/g after50 cycles at 0.1 C rate,and the initial specific discharge capacity of 115.2 mA h/g with 60.6%capacity retention after 100 cycles at 1 C In addition,the Na0.67Co0.35Ti0.20Mn0.44La0.01O2 sample shows an excellent rate capacity of 91.9 and 60.4 mA·h/g with 46.9%and 50.9%capacity retentions even at 8 C and 10 C rate after100 cycles,respectively.The promising La-substituted P2-type Na0.67Co0.35Ti0.20Mn0.45-xLaxO2 material provides a new strategy for designing high-rate performance of SIBs.
