Effects of calcination temperature on the electrochemical performance of LFMO cathode for all-solid-state energy storage

Abstract

The electrochemical performances of cathode materials depend on crystallinity and structural stability. We report improved electrochemical performances of Li2FeMn3O8 (LFMO) cathode materials synthesized using the chemical solution combustion method and the obtained powders are calcined at various temperatures such as 600 °C, 700 °C, and 900 °C. The LLCZN/PEO/LiPF6 is used as a solid electrolyte during the assembly of the coin cells. The calcining temperatures improve the crystallinity and structural stability, thereby improving the electrochemical performances of the LFMO because of the mutual diffusion region at the electrode/solid electrolyte interface. Among these, the LFMO calcined at 900 °C shows the best electrochemical performance. At 0.1 mA cm−2, the discharge capacity at the 150th cycle is 133 mAh g−1 with a Coulombic efficiency of approximately 97% and a retention rate of 85% for the 900 °C calcined sample. While the 700 °C calcined sample is 126 mAh g−1 after 150th cycles of the galvanostatic charge-discharge test, the Coulombic efficiency is maintained at about 95% and the capacity retention rate is 83%. The 600 °C calcined temperature exhibited 101 mAh g−1 with a Coulombic efficiency of 92% and a retention rate of 73% after the 150th discharge cycle. The findings suggest that the chemical solution combustion approach might be a viable way of producing nanosized LFMO as an active cathode material for lithium-ion batteries (LIB).