High entropy oxides (HEOs), with unique adjustable chemical composition characteristics and high specific capacity, show great promise as anode materials in lithium‐ion batteries. Here, a new high entropy spinel oxide, (FeCoMnZnTi) 3 O 4 , is successfully produced, and its electrochemical and charge/discharge performances are well examined. The (FeCoMnZnTi) 3 O 4 anode can deliver a comparable or even the highest discharge capacity of 1078 mAh·g –1 at 100 mA·g –1 after 100 cycles, and 404.8 mAh·g –1 at 1000 mA·g –1 after 1000 cycles. Moreover, unusual discharge stages can be evidently observed, that there is an active zone (cycles 31–80) between a decay zone (cycles 1–30) and a stable zone (cycles 81–100) during the charge/discharge cycling at 100 mA·g –1 . Based on ex situ X‐ray diffraction, transmission electron microscopy, and ex situ X‐ray photoelectron spectroscopy analysis, a novel conversion‐based Li‐storage mechanism for the HEO anode can be first proposed in this work. It suggests that the decomposition of Li 2 CO 3 in the solid electrolyte interface (SEI) layer proceeds through the release of the spin‐polarized electrons from the metallic Fe 0 and Co 0 catalysts, originating from the conversion reactions of the HEO anode, and thus resulting in the thinning of the SEI layer in this type of material.
Chen et al. (Mon,) studied this question.