Improved ionic conductivity and Li₇P₃S₁₁ solid electrolyte based all-solid state batteries for practical applications

Interface resistivity, low ionic conductivity and side reactions between the carbon/Li and Li₇P₃S₁₁ based materials are the supreme challenges in achieving high energy density all-solid state batteries. We report on improving the ionic conductivity of Li₇P₃S₁₁ (LPS) through preparation strategies and attaining the functionality of all-solid Li-ion battery with moderate capacity. LPS samples are prepared employing high energy ball milling and solid-state synthesis methods (crystalline LPS) at low temperature. LPS samples exhibit stability against Li-metal up to 5 V with wider electrochemical window. Ionic conductivity of crystalline LPS sample is seen to be one order higher than that of ball milled sample. All-solid state battery consist of crystalline LPS solid electrolyte shows charge and discharge capacity of 86.5 and 59.0 mAh/g, respectively, at the first cycle. Fabricated LPS based all-solid batteries are demonstrated for the real time applications such as operating the temperature sensors and light emitting diodes.