LiNbO3-coated LiNi0.7Co0.1Mn0.2O2 and chlorine-rich argyrodite enabling high-performance solid-state batteries under different temperatures

Surface modification of high voltage cathodes can enhance the electrochemical performance of solid-state batteries (SSBs) employing sulfide electrolytes. LiNbO3-coating is a common method, however, the role and potential of such coating on the high-nickel cathode is still under-discovered especially during extended cycling at different rates in wide temperature ranges. Herein, we carry out in-depth study of LiNbO3 coating enabled chlorine-rich argyrodite-based SSBs using LiNi0.7Co0.1Mn0.2O2 (NCM712) cathode at various C-rate (0.1, 0.5, and 1 C) and wide temperatures (-20 °C, 25 °C (RT), and 60 °C). The [email protected] electrode delivers initial discharge capacities of 80.9 and 138.9 mAh/g at 5 C under RT and 60 °C respectively with better capacity retentions of 87.5% and 88% after 600 and 300 cycles than that of the NCM712 electrode. Moreover, the [email protected] electrode also shows better electrochemical behavior than the pristine electrode under deep-freezing temperature (-20 °C). The improved battery performance of the [email protected] electrode is supported by the resistance changes between the cathode and solid electrolyte revealed by EIS and the structural evolution of active materials unraveled by TEM. This study offers a deep insight into the influence of the modification layer for the performance of SSBs and guidance of design strategy for cathode modification.