Safety issues related to flammable electrolytes in lithium-ion batteries(LIBs) remain a major challenge for their extended applications.The use of non-flammable phosphate-based electrolytes has proved the validity in ...Safety issues related to flammable electrolytes in lithium-ion batteries(LIBs) remain a major challenge for their extended applications.The use of non-flammable phosphate-based electrolytes has proved the validity in inhibiting the combustion of LIBs.However,the strong interaction between Li^(+) and phosphate leads to a dominant solid electrolyte interphase(SEI) with limited electronic shielding,resulting in the poor Li^(+) intercalation at the graphite(Gr) anode when using high-phosphate-content electrolytes.To mitigate this issue and improve Li^(+) insertion,we propose an “In-N-Out” strategy to render phosphates “noncoordinative”.By employing a combination of strongly polar solvents for a “block effect” and weakly polar solvents for a “drag effect”,we reduce the Li^(+)–phosphate interaction.As a result,phosphates remain in the electrolyte phase(“In”),minimizing their impact on the incompatibility with the Gr electrode(“Out”).We have developed a non-flammable electrolyte with high triethyl phosphate(TEP) content(>60 wt.%),demonstrating the excellent ion conductivity(5.94 mS cm^(-1) at 30 ℃) and reversible Li^(+) intercalation at a standard concentration(~1 mol L^(-1)).This approach enables the manipulation of multiple electrolyte functions and holds the promise for the development of safe electrochemical energy storage systems using non-flammable electrolytes.展开更多
All-solid-state lithium batteries(ASSLBs),which use solid electrolytes instead of liquid ones,have become a hot research topic due to their high energy and power density,ability to solve battery safety issues,and capa...All-solid-state lithium batteries(ASSLBs),which use solid electrolytes instead of liquid ones,have become a hot research topic due to their high energy and power density,ability to solve battery safety issues,and capabilities to fulfill the increasing demand for energy storage in electric vehicles and smart grid applications.Garnet-type solid electrolytes have attracted considerable interest as they meet all the properties of an ideal solid electrolyte for ASSLBs.The garnet-type Li_(7)La_(3)Zr_(2)O_(12)(LLZO)has excellent environmental stability;experiments and computational analyses showed that this solid electrolyte has a high lithium(Li)ionic conductivity(10^(-4)-10^(-3) S·cm^(-1)),an electrochemical window as wide as 6 V,stability against Li metal anode,and compatibility with most of the cathode materials.In this review,we present the fundamentals of garnet-type solid electrolytes,preparation methods,air stability,some strategies for improving the conductivity based on experimental and computational results,interfacial issues,and finally applications and challenges for future developments of LLZO solid electrolytes for ASSLBs.展开更多
基金supported by the National Key Research and Development Program of China (2022YFB2404800)the National Natural Science Foundation of China (52022013,51974031 and U22A20438)。
文摘Safety issues related to flammable electrolytes in lithium-ion batteries(LIBs) remain a major challenge for their extended applications.The use of non-flammable phosphate-based electrolytes has proved the validity in inhibiting the combustion of LIBs.However,the strong interaction between Li^(+) and phosphate leads to a dominant solid electrolyte interphase(SEI) with limited electronic shielding,resulting in the poor Li^(+) intercalation at the graphite(Gr) anode when using high-phosphate-content electrolytes.To mitigate this issue and improve Li^(+) insertion,we propose an “In-N-Out” strategy to render phosphates “noncoordinative”.By employing a combination of strongly polar solvents for a “block effect” and weakly polar solvents for a “drag effect”,we reduce the Li^(+)–phosphate interaction.As a result,phosphates remain in the electrolyte phase(“In”),minimizing their impact on the incompatibility with the Gr electrode(“Out”).We have developed a non-flammable electrolyte with high triethyl phosphate(TEP) content(>60 wt.%),demonstrating the excellent ion conductivity(5.94 mS cm^(-1) at 30 ℃) and reversible Li^(+) intercalation at a standard concentration(~1 mol L^(-1)).This approach enables the manipulation of multiple electrolyte functions and holds the promise for the development of safe electrochemical energy storage systems using non-flammable electrolytes.
基金supported by the National Key R&D Program of China(Nos.2018YFB0905600 and 2017YFB0310400)the National Natural Science Foundation of China(No.51972246)+2 种基金Fundamental Research Funds for the Central Universities in China,State Key Laboratory of Advanced Electromagnetic Engineering and Technology(Huazhong University of Science and Technology)the"111"project(No.B13035)the Science and Technology Project of Global Energy Interconnection Research Institute Co.,Ltd.(No.SGGR0000WLJS1801080).
文摘All-solid-state lithium batteries(ASSLBs),which use solid electrolytes instead of liquid ones,have become a hot research topic due to their high energy and power density,ability to solve battery safety issues,and capabilities to fulfill the increasing demand for energy storage in electric vehicles and smart grid applications.Garnet-type solid electrolytes have attracted considerable interest as they meet all the properties of an ideal solid electrolyte for ASSLBs.The garnet-type Li_(7)La_(3)Zr_(2)O_(12)(LLZO)has excellent environmental stability;experiments and computational analyses showed that this solid electrolyte has a high lithium(Li)ionic conductivity(10^(-4)-10^(-3) S·cm^(-1)),an electrochemical window as wide as 6 V,stability against Li metal anode,and compatibility with most of the cathode materials.In this review,we present the fundamentals of garnet-type solid electrolytes,preparation methods,air stability,some strategies for improving the conductivity based on experimental and computational results,interfacial issues,and finally applications and challenges for future developments of LLZO solid electrolytes for ASSLBs.
