Hydrolysis mechanism of Li-argyrodite Li6PS5Cl in air
All-solid-state lithium-ion batteries(ASSLBs)with solid state electrolytes(SSE),regarded as next-generation battery system,have attracted most of the research and industrial interest in the electrochemical storage field due to their higher energy density,wider voltage window,safety and other superior performance.Seeking promising solid-sate electrolytes with high ionic conductivity and excellent electrochemical stability plays the key role in practicing ASSLBs.Li-argyrodites show high ionic conductivity and stable electrochemical properties,which are advantageous to ASSLIBs.However,as most sulfide solid electrolytes show poor stability in air,Li-argyrodites would react with H2O molecules in the air and release harmful H2S gas.We have carried out first-principles calculations on the failure mechanism of Li-argyrodites based on the hydrolysis of Li6PS5Cl.Two possible hydrolysis paths for H2O molecule on the Li6PS5Cl surface are found,with single or dual H2O molecules,respectively.The dynamic results show that both oxygen atoms and sulfur vacancies could diffuse on the surface.However,they are difficult to migrate in the bulk.Thermodynamic calculations show that the thermodynamic stability of Li6PS5Cl decreases gradually with the contin-uous hydrolysis reaction.The effect of doping Sn in Li6PS5Cl is further investigated,which explains the inhibiting mechanism of Sn-doping in Li6PS5Cl from the perspective of kinetics.Our studies also show that Sn doping mainly inhibits the hydrolysis of Li6PS5Cl by pre-venting the decomposition of OH-when involving single H2O molecule,while it obstructs the decomposition of the absorbed H2O when involving dual H2O molecules.
mechanism、hydrolysis、li-argyrodite
42
TH16;F820.5;TN249
2023-03-15(万方平台首次上网日期,不代表论文的发表时间)
共9页
47-55