Parasitic Reaction Alleviation of Ni-Rich Cathode Active Materials at Elevated Temperatures Using a Perovskite-Type Lanthanum Iron Oxide

Lithium-ion batteries (LIBs) are dominantly used as energy storage systems for mobile devices and electric vehicles. Ni-rich Li[NixCoyAl1-x-y]O2 (NCA) is considered a promising cathode material for the next-generation LIBs because of its high theoretical capacity. However, Ni-rich cathodes are operated strictly within a limited temperature range to avoid thermal runaway. At elevated temperatures, their structural stability is damaged, inducing severe capacity fading. In this study, we used a simple wet chemical synthesis technique to coat an NCA cathode material with a perovskite-type LFO. The resulting LFO-coated NCA cathode material exhibited improved electrochemical properties and enhanced structural stability at high temperatures. Our electrochemical performance revealed that the LFO-coated NCA cathode material exhibits higher initial discharge capacity and better capacity retention after cycling than bare NCA, especially at elevated temperatures and higher C-rates. Furthermore, our results suggest that the LFO coating layer effectively protects the active cathode material from the parasitic reaction during cycling, which can cause capacity fading. The protective layer formed by the LFO coating inhibits the reaction between the active material and the electrolyte, thereby preserving the structural integrity and electrochemical performance of the cathode material. These findings provide insight into the development of the next-generation LIBs that can operate at higher temperatures and have better electrochemical performance.