LiTaO3 mixing effects to suppress side reactions at the LiNi0.8Co0.1Mn0.1O2 cathode and Li5.3PS4.3Cl1.7 solid electrolyte of all-solid-state lithium batteries

Suppressing the side reactions at the solid electrolyte-electrode interface in all-solid-state battery (ASSB) is very important aspect of improving battery performance. Coating an electrochemically stable material on the surface of cathode has been used to suppress the side reactions occurring at interface between solid electrolyte and cathode. However, to achieve effective suppression, the thickness of the coating film must be thin and uniform. Moreover, an expensive ethoxide series typically must be used as a starting material. In this study, LiTaO3 coating material was simply mixed with the solid electrolyte to measure the effect of suppressing side reactions. To synthesize the solid electrolyte Li5.3PS4.3Cl1.7 and the mixing material LiTaO3, high-energy ball milling and wet milling methods were used, respectively. The structural characteristics of the prepared solid electrolytes were studied by powder X-ray diffraction. The LiTaO3 mixed solid electrolyte based ASSB showed a high discharge capacity of 177.3 mAh/g in the initial cycle, whereas the bare solid electrolyte (Li5.3PS4.3Cl1.7) based ASSB showed a discharge capacity of 159.1 mAh/g. To understand the side reactions, electrochemical impedance spectroscopy (EIS) analysis was performed after galvanostatic charge-discharge cycles. The EIS analysis confirmed that the side reaction between a solid electrolyte and a cathode was effectively suppressed in LiTaO3 mixed solid electrolyte based ASSBs.