Solid electrolytes face challenges in solid-state sodium batteries(SSSBs)because of limited ionic conductivity,increased interfacial resistance,and sodium dendrite issues.In this study,we adopted a unique Sn4+doping s...Solid electrolytes face challenges in solid-state sodium batteries(SSSBs)because of limited ionic conductivity,increased interfacial resistance,and sodium dendrite issues.In this study,we adopted a unique Sn4+doping strategy for Na_(3.2)Zr_(2)Si_(2.2)P_(0.8)O_(12)(NZSP)that caused a partial structural transition from the monoclinic(C2/c)phase to the rhombohedral(R-3c)phase in Na_(3.2)Zr_(1.9)Sn_(0.1)Si_(2.2)P_(0.8)O_(12)(NZSnSP1).X-ray diffraction(XRD)patterns and high-resolution transmission electron microscopy analyses were used to confirm this transition,where rhombohedral NZSnSP1 showed an increase in the Na2-O bond length compared with monoclinic NZSnSP1,increasing its triangular bottleneck areas and noticeably enhancing Na+ionic conductivity,a higher Na transference number,and lower electronic conductivity.NZSnSP1 also showed exceptionally high compatibility with Na metal with an increased critical current density,as evidenced by symmetric cell tests.The SSSB,fabricated using Na_(0.9)Zn_(0.22)Fe_(0.3)Mn_(0.48)O_(2)(NZFMO),Na metal,and NZSnSP1 as the cathode,anode,and the solid electrolyte and separator,respectively,maintains 65.86%of retention in the reversible capacity over 300 cycles within a voltage range of 2.0-4.0 V at 25℃ at 0.1 C.The in-situ X-ray diffraction and X-ray absorption analyses of the P and Zr K-edges confirmed that NZSnSP1 remained highly stable before and after electrochemical cycling.This crystal structure modification strategy enables the synthesis of ideal solid electrolytes for practical SSSBs.展开更多
High-voltage medium-nickel low-cobalt lithium layered oxide cathode materials are becoming a popular development route for high-energy lithium-ion batteries due to their relatively high capacity,low cost,and improved ...High-voltage medium-nickel low-cobalt lithium layered oxide cathode materials are becoming a popular development route for high-energy lithium-ion batteries due to their relatively high capacity,low cost,and improved safety.Unfortunately,capacity fading derived from surface lithium residue,electrode-electrolyte interfacial side reactions,and bulk structure degradation severely limits large-scale commercial utilization.In this work,an ultrathin and uniform NASICON-type Li_(3)V_(2)(PO_(4))_(3)(LVP)nanoscale functional coating is formed in situ by utilizing residual lithium to enhance the lithium storage performance of LiNi_(0.6)Co0.05Mn_(0.35)O_(2)(NCM)cathode.The GITT and ex-situ EIS and XPS demonstrate exceptional Li+diffusion and conductivity and attenuated interfacial side reactions,improving the electrode-electrolyte interface stability.The variable temperature in-situ XRD demonstrates delayed phase transition temperature to improve thermal stability.The battery in-situ XRD displays the singlephase H1-H2 reaction and weakened harmful H3 phase transition,minimizing the bulk mechanical degradation.These improvements are attributed to the removal of surface residual lithium and the formation of NASICON-type Li_(3)V_(2)(PO_(4))_(3)functional coatings with stable structure and high ionic and electronic conductivity.Consequently,the obtained NCM@LVP delivers a higher capacity retention rate(97.1%vs.79.6%)after 150 cycles and a superior rate capacity(87 mAh·g^(-1)vs.58 mAh·g^(-1))at a 5 C current density than the pristine NCM under a high cut-off voltage of 4.5 V.This work suggests a clever way to utilize residual lithium to form functional coatings in situ to improve the lithium storage performance of high-voltage medium-nickel low-cobalt cathode materials.展开更多
NASICON (Na superionic conductor)-type cathode materials for sodium-ion batteries (SIBs) have attractedextensive attention due to their mechanically robust three-dimensional (3D) framework, which has sufficient opench...NASICON (Na superionic conductor)-type cathode materials for sodium-ion batteries (SIBs) have attractedextensive attention due to their mechanically robust three-dimensional (3D) framework, which has sufficient openchannels for fast Na^(+) transportation. However, they usually suffer from inferior electronic conductivity and lowcapacity, which severely limit their practical applications. To solve these issues, we need to deeply understand thestructural evolution, redox mechanisms, and electrode/electrolyte interface reactions during cycling. Recently,rapid developments in synchrotron X-ray techniques, neutron-based resources, magnetic resonance, as well asoptical and electron microscopy have brought numerous opportunities to gain deep insights into the Na-storagebehaviors of NASICON cathodes. In this review, we summarize the detection principles of advanced characterization techniques used with typical NASICON-structured cathode materials for SIBs. The special focus is on bothoperando and ex situ techniques, which help to investigate the relationships among phase, composition, andvalence variations within electrochemical responses. Fresh electrochemical measurements and theoretical computations are also included to reveal the kinetics and energy-storage mechanisms of electrodes upon charge/discharge. Finally, we describe potential new developments in NASICON-cathodes with optimized SIB systems,foreseeing a bright future for them, achievable through the rational application of advanced diagnostic methods.展开更多
The development of high-energy and long-lifespan NASICON-type cathode materials for sodium-ion batteries has always been a research hotspot but a daunting challenge.Although Na_(4)MnCr(PO_(4))_(3)has emerged as one of...The development of high-energy and long-lifespan NASICON-type cathode materials for sodium-ion batteries has always been a research hotspot but a daunting challenge.Although Na_(4)MnCr(PO_(4))_(3)has emerged as one of the most promising high-energy-density cathode materials owing to its three-electron reactions,it still suffers from serious structural distortion upon repetitive charge/discharge processes caused by the Jahn-Teller active Mn^(3+).Herein,the selective substitution of Cr by Zr in Na_(4)MnCr(PO_(4))_(3)was explored to enhance the structural stability,due to the pinning effect of Zr ions and the≈2.9-electron reactions,as-prepared Na_(3.9)MnCr_(0.9)Zr_(0.1)(PO_(4))_(3)/C delivers a high capacity retention of 85.94%over 500 cycles at 5 C and an ultrahigh capacity of 156.4 mAh g^(-1)at 0.1 C,enabling the stable energy output as high as 555.2 Wh kg^(-1).Moreover,during the whole charge/discharge process,a small volume change of only 6.7%was verified by in situ X-ray diffraction,and the reversible reactions of Cr^(3+)/Cr^(4+),Mn^(3+)/Mn^(4+),and Mn^(2+)/Mn^(3+)redox couples were identified via ex situ X-ray photoelectron spectroscopy analyses.Galvanostatic intermittent titration technique tests and density functional theory calculations further demonstrated the fast reaction kinetics of the Na_(3.9)MnCr_(0.9)Zr_(0.1)(PO_(4))_(3)/C electrode.This work offers new opportunities for designing high-energy and high-stability NASICON cathodes by ion doping.展开更多
Using stable inorganic solid electrolyte to replace organic liquid electrolyte could significantly reduce potential safety risks of rechargeable batteries. Na-superionic conductor （NASICON）-structured solid electrol...Using stable inorganic solid electrolyte to replace organic liquid electrolyte could significantly reduce potential safety risks of rechargeable batteries. Na-superionic conductor （NASICON）-structured solid electrolyte is one of the most promising sodium solid electrolytes and can be employed in solid-state sodium batteries. In this work, a NASICON-structured solid electrolyte Na3.1Zr1.95Mg0.05Si2PO12 was synthesized through a facile solid-state reaction, yielding high sodium-ionic conductivity of 1.33 × 10-3 S.cm^-1 at room temperature. The results indicate that Mg^2＋ is a suitable and economical substitution ion to replace Zr^4＋, and this synthesis route can be scaled up for powder preparation with low cost. In addition to electrolyte material preparation, solid-state batteries with Na3.1Zr1.95Mg0.05Si2PO12 as electrolyte were assembled. A specific capacity of 57.9 mAh·g^-1 is maintained after 100 cycles under a current density of 0.5C rate at room temperature. The favorable cycling performance of the solid-state battery suggests that Na3.1Zr1.95Mg0.05Si2PO12 is an ideal electrolyte candidate for solid-state sodium batteries.展开更多
制作了一种新型微型结构CO2传感器，该传感器采用Al2O3陶瓷片作为衬底，sol—gel法制备的固体电解质NASICON（sodium super ionic conductor）材料为离子导电层，复合碳酸盐Li2CO3-BaC03（摩尔比为1：1.5）为敏感电极。该传感器在CO2浓...制作了一种新型微型结构CO2传感器，该传感器采用Al2O3陶瓷片作为衬底，sol—gel法制备的固体电解质NASICON（sodium super ionic conductor）材料为离子导电层，复合碳酸盐Li2CO3-BaC03（摩尔比为1：1.5）为敏感电极。该传感器在CO2浓度为（500-5000）×10^-6体积分数范围内表现出良好的敏感特性，灵敏度达到67.3mV／decade（毫伏／10×10^-6体积分数），并且功耗由原来的1．08w降到0．72W。微型元件的响应恢复时间分别为20S和58S。展开更多
Despite the promising potential of NaTi_(2)(PO_(4))_(3)as desalination battery electrode,its mediocre seawater desalination capacity and durability fail to meet the requirements of practical application.Herein,the sub...Despite the promising potential of NaTi_(2)(PO_(4))_(3)as desalination battery electrode,its mediocre seawater desalination capacity and durability fail to meet the requirements of practical application.Herein,the substitution of Ti by Fe in NaTi_(2)(PO_(4))_(3)(NT_(2-x)FxP),which possesses a stronger electronegativity relative to Ti,can regulate the electronic structure,thus facilitating charge transfer and ion diffusion during the desalination process.The kinetic and thermodynamic facilitation of NT_(2-x)FxP is clarified by the electrochemical analyses and DFT calculations.Meanwhile,the additional redox center and solid-solution reaction mechanism induced by Fe-dopant further contribute to a superior desalination performance of NT_(2-x)FxP in different seawater media.Benefitting from the multifunctional effect of Fe-dopant,the optimal NT1.7F0.3P delivers a large salt removal capacity(173.6 mg g^(-1))with an ultrahigh salt removal rate(8.48 mg g^(-1)min^(-1)),and maintains 96.6%of desalination capacity after 500 cycles in natural seawater.Furthermore,the assembled NT1.7F0.3P||NaFeHCF rocking-chair desalination battery(RCDB)demonstrates a higher desalination performance than that of reported RCDB systems,and can desalinate natural seawater to freshwater standards under continuous desalination mode for the first time in RCDB system.This work provides a facile but effective strategy to modulate the electronic structure of NaTi_(2)(PO_(4))_(3)for RCDB,and exploits a new perspective for developing scalable RCDB devices for continuous desalinating real seawater to freshwater.展开更多
NASICON type Li_(3)Zr_(2)Si_(2)PO_(12)can be synthesized via cation exchange method with Na_(3)Zr_(2)Si_(2)PO_(12)as precursor,which retains the skeleton structure and achieves an ionic conductivity higher than 3 mS c...NASICON type Li_(3)Zr_(2)Si_(2)PO_(12)can be synthesized via cation exchange method with Na_(3)Zr_(2)Si_(2)PO_(12)as precursor,which retains the skeleton structure and achieves an ionic conductivity higher than 3 mS cm^(-1)at room temperature.However,large-scale fabrication via cation exchange reaction seems unlikely considering the expensive precursors and complicated preparation process.Herein,the viability of solid-state reaction to prepare Li_(3)Zr_(2)Si_(2)PO_(12)is explored,which has important implication for its industrialization.The sintering was conducted using the raw materials of LiOH,SiO_(2),ZrO_(2)and NH_(4)H_(2)PO_(4)with the nominal stoichiometric ratio of Li_(3)Zr_(2)Si_(2)PO_(12).The results show that the final product is a Li_(3)PO_(4)·2ZrSiO_(4)composite with negligible Li+conductivity,other than the expected Li_(3)Zr_(2)Si_(2)PO_(12)with high Li+conductivity.Combined with thermodynamic calculations based on density functional theory(DFT),the competition between Li_(3)PO_(4)·2ZrSiO_(4)and Li_(3)Zr_(2)Si_(2)PO_(12)with NASICON phase is analyzed.It was found that the formation energy(AG)of Li_(3)PO_(4)·2ZrSiO_(4)is lower than that of Li_(3)Zr_(2)Si_(2)PO_(12).In addition,the decomposition of Li_(3)Zr_(2)Si_(2)PO_(12)with Li_(3)PO_(4)-2ZrSiO_(4)as products is a thermodynamically spontaneous reaction.The influences related to the coordination structures on the structural stability of NZSP are discussed as well.These results demonstrate that the fabrication of Li_(3)Zr_(2)Si_(2)PO_(12)through high-temperature sintering is difficult,and the development of a synthetic method with mild conditions is essential for the Li_(3)Zr_(2)Si_(2)PO_(12)preparation.展开更多
基金supported by the National Research Foundation of Korea(RS-2024-00404414)the National Research Council of Science&Technology(NST,No.GTL24011-000)funded by the Ministry of Science and ICTsupported by the KIST Institutional Program(Project No.2E33270).
文摘Solid electrolytes face challenges in solid-state sodium batteries(SSSBs)because of limited ionic conductivity,increased interfacial resistance,and sodium dendrite issues.In this study,we adopted a unique Sn4+doping strategy for Na_(3.2)Zr_(2)Si_(2.2)P_(0.8)O_(12)(NZSP)that caused a partial structural transition from the monoclinic(C2/c)phase to the rhombohedral(R-3c)phase in Na_(3.2)Zr_(1.9)Sn_(0.1)Si_(2.2)P_(0.8)O_(12)(NZSnSP1).X-ray diffraction(XRD)patterns and high-resolution transmission electron microscopy analyses were used to confirm this transition,where rhombohedral NZSnSP1 showed an increase in the Na2-O bond length compared with monoclinic NZSnSP1,increasing its triangular bottleneck areas and noticeably enhancing Na+ionic conductivity,a higher Na transference number,and lower electronic conductivity.NZSnSP1 also showed exceptionally high compatibility with Na metal with an increased critical current density,as evidenced by symmetric cell tests.The SSSB,fabricated using Na_(0.9)Zn_(0.22)Fe_(0.3)Mn_(0.48)O_(2)(NZFMO),Na metal,and NZSnSP1 as the cathode,anode,and the solid electrolyte and separator,respectively,maintains 65.86%of retention in the reversible capacity over 300 cycles within a voltage range of 2.0-4.0 V at 25℃ at 0.1 C.The in-situ X-ray diffraction and X-ray absorption analyses of the P and Zr K-edges confirmed that NZSnSP1 remained highly stable before and after electrochemical cycling.This crystal structure modification strategy enables the synthesis of ideal solid electrolytes for practical SSSBs.
基金the National Key R&D Program of China(No.2017YFE0198100)the National Natural Science Foundation of China(No.21975250)+1 种基金the Key R&D Program of Jilin Province(No.20220201132GX),the Key R&D Program of Hubei Province(No.2022BAA084)the Capital Construction Fund Projects within the Budget of Jilin Province(2021C037-2).
文摘High-voltage medium-nickel low-cobalt lithium layered oxide cathode materials are becoming a popular development route for high-energy lithium-ion batteries due to their relatively high capacity,low cost,and improved safety.Unfortunately,capacity fading derived from surface lithium residue,electrode-electrolyte interfacial side reactions,and bulk structure degradation severely limits large-scale commercial utilization.In this work,an ultrathin and uniform NASICON-type Li_(3)V_(2)(PO_(4))_(3)(LVP)nanoscale functional coating is formed in situ by utilizing residual lithium to enhance the lithium storage performance of LiNi_(0.6)Co0.05Mn_(0.35)O_(2)(NCM)cathode.The GITT and ex-situ EIS and XPS demonstrate exceptional Li+diffusion and conductivity and attenuated interfacial side reactions,improving the electrode-electrolyte interface stability.The variable temperature in-situ XRD demonstrates delayed phase transition temperature to improve thermal stability.The battery in-situ XRD displays the singlephase H1-H2 reaction and weakened harmful H3 phase transition,minimizing the bulk mechanical degradation.These improvements are attributed to the removal of surface residual lithium and the formation of NASICON-type Li_(3)V_(2)(PO_(4))_(3)functional coatings with stable structure and high ionic and electronic conductivity.Consequently,the obtained NCM@LVP delivers a higher capacity retention rate(97.1%vs.79.6%)after 150 cycles and a superior rate capacity(87 mAh·g^(-1)vs.58 mAh·g^(-1))at a 5 C current density than the pristine NCM under a high cut-off voltage of 4.5 V.This work suggests a clever way to utilize residual lithium to form functional coatings in situ to improve the lithium storage performance of high-voltage medium-nickel low-cobalt cathode materials.
基金Financial support from the National Natural Science Foundation of China(22075016 and 21805007)Fundamental Research Funds for the Central Universities(FRF-TP-20-020A3)111 Project(B12015 and B170003)is gratefully acknowledged.
文摘NASICON (Na superionic conductor)-type cathode materials for sodium-ion batteries (SIBs) have attractedextensive attention due to their mechanically robust three-dimensional (3D) framework, which has sufficient openchannels for fast Na^(+) transportation. However, they usually suffer from inferior electronic conductivity and lowcapacity, which severely limit their practical applications. To solve these issues, we need to deeply understand thestructural evolution, redox mechanisms, and electrode/electrolyte interface reactions during cycling. Recently,rapid developments in synchrotron X-ray techniques, neutron-based resources, magnetic resonance, as well asoptical and electron microscopy have brought numerous opportunities to gain deep insights into the Na-storagebehaviors of NASICON cathodes. In this review, we summarize the detection principles of advanced characterization techniques used with typical NASICON-structured cathode materials for SIBs. The special focus is on bothoperando and ex situ techniques, which help to investigate the relationships among phase, composition, andvalence variations within electrochemical responses. Fresh electrochemical measurements and theoretical computations are also included to reveal the kinetics and energy-storage mechanisms of electrodes upon charge/discharge. Finally, we describe potential new developments in NASICON-cathodes with optimized SIB systems,foreseeing a bright future for them, achievable through the rational application of advanced diagnostic methods.
基金Financial support from the National Natural Science Foundation of China(22075016 and 22103057)Fundamental Research Funds for the Central Universities(FRF-TP-20-020A3 and QNXM20220060)+1 种基金Interdisciplinary Research Project for Young Teachers of USTB(FRF-IDRY-21-011)111 Project(B170003 and B12015)
文摘The development of high-energy and long-lifespan NASICON-type cathode materials for sodium-ion batteries has always been a research hotspot but a daunting challenge.Although Na_(4)MnCr(PO_(4))_(3)has emerged as one of the most promising high-energy-density cathode materials owing to its three-electron reactions,it still suffers from serious structural distortion upon repetitive charge/discharge processes caused by the Jahn-Teller active Mn^(3+).Herein,the selective substitution of Cr by Zr in Na_(4)MnCr(PO_(4))_(3)was explored to enhance the structural stability,due to the pinning effect of Zr ions and the≈2.9-electron reactions,as-prepared Na_(3.9)MnCr_(0.9)Zr_(0.1)(PO_(4))_(3)/C delivers a high capacity retention of 85.94%over 500 cycles at 5 C and an ultrahigh capacity of 156.4 mAh g^(-1)at 0.1 C,enabling the stable energy output as high as 555.2 Wh kg^(-1).Moreover,during the whole charge/discharge process,a small volume change of only 6.7%was verified by in situ X-ray diffraction,and the reversible reactions of Cr^(3+)/Cr^(4+),Mn^(3+)/Mn^(4+),and Mn^(2+)/Mn^(3+)redox couples were identified via ex situ X-ray photoelectron spectroscopy analyses.Galvanostatic intermittent titration technique tests and density functional theory calculations further demonstrated the fast reaction kinetics of the Na_(3.9)MnCr_(0.9)Zr_(0.1)(PO_(4))_(3)/C electrode.This work offers new opportunities for designing high-energy and high-stability NASICON cathodes by ion doping.
基金financially supported by the National Key Research and Development Program of China(No.2016YFB0100105)Strategic Priority Program of the Chinese Academy of Sciences(No.XDA09010203)+1 种基金Zhejiang Provincial Natural Science Foundation of China(Nos.LD18E020004,LY18E020018 and LY18E030011)the Youth Innovation Promotion Association CAS(No.2017342)
文摘Using stable inorganic solid electrolyte to replace organic liquid electrolyte could significantly reduce potential safety risks of rechargeable batteries. Na-superionic conductor （NASICON）-structured solid electrolyte is one of the most promising sodium solid electrolytes and can be employed in solid-state sodium batteries. In this work, a NASICON-structured solid electrolyte Na3.1Zr1.95Mg0.05Si2PO12 was synthesized through a facile solid-state reaction, yielding high sodium-ionic conductivity of 1.33 × 10-3 S.cm^-1 at room temperature. The results indicate that Mg^2＋ is a suitable and economical substitution ion to replace Zr^4＋, and this synthesis route can be scaled up for powder preparation with low cost. In addition to electrolyte material preparation, solid-state batteries with Na3.1Zr1.95Mg0.05Si2PO12 as electrolyte were assembled. A specific capacity of 57.9 mAh·g^-1 is maintained after 100 cycles under a current density of 0.5C rate at room temperature. The favorable cycling performance of the solid-state battery suggests that Na3.1Zr1.95Mg0.05Si2PO12 is an ideal electrolyte candidate for solid-state sodium batteries.
文摘制作了一种新型微型结构CO2传感器，该传感器采用Al2O3陶瓷片作为衬底，sol—gel法制备的固体电解质NASICON（sodium super ionic conductor）材料为离子导电层，复合碳酸盐Li2CO3-BaC03（摩尔比为1：1.5）为敏感电极。该传感器在CO2浓度为（500-5000）×10^-6体积分数范围内表现出良好的敏感特性，灵敏度达到67.3mV／decade（毫伏／10×10^-6体积分数），并且功耗由原来的1．08w降到0．72W。微型元件的响应恢复时间分别为20S和58S。
基金supported by the National Natural Science Foundation of China(52100084)。
文摘Despite the promising potential of NaTi_(2)(PO_(4))_(3)as desalination battery electrode,its mediocre seawater desalination capacity and durability fail to meet the requirements of practical application.Herein,the substitution of Ti by Fe in NaTi_(2)(PO_(4))_(3)(NT_(2-x)FxP),which possesses a stronger electronegativity relative to Ti,can regulate the electronic structure,thus facilitating charge transfer and ion diffusion during the desalination process.The kinetic and thermodynamic facilitation of NT_(2-x)FxP is clarified by the electrochemical analyses and DFT calculations.Meanwhile,the additional redox center and solid-solution reaction mechanism induced by Fe-dopant further contribute to a superior desalination performance of NT_(2-x)FxP in different seawater media.Benefitting from the multifunctional effect of Fe-dopant,the optimal NT1.7F0.3P delivers a large salt removal capacity(173.6 mg g^(-1))with an ultrahigh salt removal rate(8.48 mg g^(-1)min^(-1)),and maintains 96.6%of desalination capacity after 500 cycles in natural seawater.Furthermore,the assembled NT1.7F0.3P||NaFeHCF rocking-chair desalination battery(RCDB)demonstrates a higher desalination performance than that of reported RCDB systems,and can desalinate natural seawater to freshwater standards under continuous desalination mode for the first time in RCDB system.This work provides a facile but effective strategy to modulate the electronic structure of NaTi_(2)(PO_(4))_(3)for RCDB,and exploits a new perspective for developing scalable RCDB devices for continuous desalinating real seawater to freshwater.
基金supported by the Key R&D Program of Shandong Province(2021CXGC010401)the National Natural Science Foundation of China(U1932205 and 52002197)+1 种基金the Open Project of Provincial Application Characteristic Disciplines of Hunan Institute of Technology(KFA22013)the Natural Science Foundation of Hunan Province(2023JJ50101).
文摘NASICON type Li_(3)Zr_(2)Si_(2)PO_(12)can be synthesized via cation exchange method with Na_(3)Zr_(2)Si_(2)PO_(12)as precursor,which retains the skeleton structure and achieves an ionic conductivity higher than 3 mS cm^(-1)at room temperature.However,large-scale fabrication via cation exchange reaction seems unlikely considering the expensive precursors and complicated preparation process.Herein,the viability of solid-state reaction to prepare Li_(3)Zr_(2)Si_(2)PO_(12)is explored,which has important implication for its industrialization.The sintering was conducted using the raw materials of LiOH,SiO_(2),ZrO_(2)and NH_(4)H_(2)PO_(4)with the nominal stoichiometric ratio of Li_(3)Zr_(2)Si_(2)PO_(12).The results show that the final product is a Li_(3)PO_(4)·2ZrSiO_(4)composite with negligible Li+conductivity,other than the expected Li_(3)Zr_(2)Si_(2)PO_(12)with high Li+conductivity.Combined with thermodynamic calculations based on density functional theory(DFT),the competition between Li_(3)PO_(4)·2ZrSiO_(4)and Li_(3)Zr_(2)Si_(2)PO_(12)with NASICON phase is analyzed.It was found that the formation energy(AG)of Li_(3)PO_(4)·2ZrSiO_(4)is lower than that of Li_(3)Zr_(2)Si_(2)PO_(12).In addition,the decomposition of Li_(3)Zr_(2)Si_(2)PO_(12)with Li_(3)PO_(4)-2ZrSiO_(4)as products is a thermodynamically spontaneous reaction.The influences related to the coordination structures on the structural stability of NZSP are discussed as well.These results demonstrate that the fabrication of Li_(3)Zr_(2)Si_(2)PO_(12)through high-temperature sintering is difficult,and the development of a synthetic method with mild conditions is essential for the Li_(3)Zr_(2)Si_(2)PO_(12)preparation.
