High Entropy Oxide Duplex Yolk–Shell Structure with Isogenic Amorphous/Crystalline Heterophase as a Promising Anode Material for Lithium‐Ion Batteries

Abstract Achieving composition and structure regulation on high entropy materials is a big challenge but will give this kind of new materials a huge boost in energy storage. Herein, a novel high entropy oxide ((CrMnFeCoNi) 3 O 4 ) duplex yolk–shell structure (DYSHEO) with isogenic amorphous/crystalline heterophase are designed and successfully prepared through a simple microthermal solvothermal reaction followed by mesothermal calcination. The microthermal solvothermal reaction results in high entropy precursor with duplex yolk–shell structure, while the mesothermal calcination (annealing temperature at 450 °C) realizes the precursor transformation to (CrMnFeCoNi) 3 O 4 (DYSHEO‐450) with isogenic amorphous/crystalline heterophase structure. The high entropy effect, the duplex yolk–shell structure, and the isogenic amorphous/crystalline heterophase endow DYSHEO‐450 great advantages as lithium‐ion battery anode including reducing ion migration obstruction, accommodating volume expansion, and alleviating the stress. Accordingly, DYSHEO‐450 exhibits high capacities of 1721 mAh g −1 @0.5 A g −1 , and 1356 mAh g −1 @1 A g −1 after 500 cycles with a capacity retention rate of 90.3%. It also shows excellent performances in practical application as anode of a coin‐type full cell. This work provides new ideas and directions for the structural regulation of high‐entropy materials.