Application of Artificial Interphase on Ni-Rich Cathode Materials in All Solid State Li-Ion Batteries

Abstract

Among many cathode materials, nickel-rich LiNi0.8Co0.1Mn0.1O2 (NCM 811) has been spotlighted as one of the most feasible candidates for next-generation LIBs because of its high discharge capacity (~200 mAh/g). However, NCM 811 shows significant performance degradation, which is mostly attributed to cation mixing, surface side reactions, and intrinsic structural instability originating from the large volume changes during repeated cycling.Conventional lithium ion batteries (LIB) normally use flammable nonaqueous liquid electrolytes, resulting in a serious safety issue in use. In this respect, all solid state lithium ion batteries (SSLIBs) are regarded as a fundamental solution to address the safety issue by using a solid state electrolyte (SSE) in place of the conventional liquid one.This study assess the performance of NCM811 cathode for all-solid-state batteries based on hybrid PEO-ceramic solid electrolyte. Artificial CEI coating layer has been developed in order to prevent direct contact of electrolyte with the cathode, thus avoid the negative effects, such as side reactions, on NCM 811. The incorporation of ceramic materials results composite electrolytes, containing inert fillers, offer improved mechanical stability under high operating temperature.It is demonstrated that the polymer of hybrid electrolytes can penetrate into cathode, providing a good Li+ transfer channel inside the battery under high operating temperature. Moreover, the protective coating on NCM811 effectively improve the electrochemical stability.(This work is supported by Ministry of Science and Technology, Taiwan under contract number: MOST 108-3116-F002-008)