Interface engineering of high entropy Oxide@Polyaniline heterojunction enables highly stable and excellent lithium ion storage performance

High-Entropy Oxide (HEO) is a new material system for lithium-ion battery (LIB) electrode materials; however, the poor electrical conductivity and instability of the electrode structure limit the further improvement of their electrochemical performance. In this work, we demonstrate that a highly stable and excellent Li-ion storage performance can be achieved by interfacial engineering of surface-chemically modified HEO@polyaniline het-erojunctions. Polyaniline-coated HEO (HEO-MP) was prepared by polymerization of aniline on the surface of ball-milled micrometer-sized HEO (HEO-M). HEO-MP anodes exhibit high rate performance (325 mA h g-1 at 10 A g(-1)) and extremely long cycling stability (261 mA h g-1 at 4.0 A g-1 after 3200 cycles), both representing the best results so far. The improved electrochemical performance can be attributed to the conductive PANI coating, which buffers volume changes and maintains structural integrity during cycling, prevents side reactions between electrolyte and electrode materials, suppresses overproduction of SEI, and enhances ionic/electronic transport. This work demonstrates that surface interface engineering is a key step to significantly improve the performance of HEO anodes in LIBs, which can be progressed on the road to its practical applications.