Dense Sphene-type Solid Electrolyte Through Rapid Sintering for Solid-state Lithium Metal Battery

The sphene-type solid electrolyte with high ionic conductivity has been designed for solid-state lithium metal battery.However,the practical applications of solid electrolytes are still suffered by the low relative density and long sintering time of tens of hous with large energy consumption.Here,we introduced the spark plasma sintering technology for fabricating the sphene-type Li1.125Ta0.875Zr0.125SiO5 solid electrolyte.The dense electrolyte pellet with high relative density of ca.97.4% and ionic conductivity of ca.1.44×10^-5S/cm at 30℃ can be obtained by spark plasma sintering process within the extremely short time of only ca.0.1h.Also the solid electrolyte provides stable electrochemical window of ca.6.0V(vs.Li^+/Li)and high electrochemical interface stability toward Li metal anodc.With the enhanced interfacial contacts between electrodes and electrolyte pellet by the in-situ formed polymer electrolyte,the solid-state lithium metal battery with LiFePO4 cathode can deliver the initial discharge capacity of ca.154mA·h/g at 0.1C and the reversible capacity of ca.132mA·h/g after 70 cycles with high Coulombic efficienty of 99.5% at 55℃.Therefore,this study demonstrates a rapid and energy efficient sintering strategy for fabricating the solid electrolyte with dense structure and high ionic conductivity that can be practically applied in solid-state lithium metal batteries with high energy densities and safeties.