Preparation and sodium storage properties of spinel‐type (Cr_0.2Fe_0.2Mn_0.2Ni_0.2Co_0.2)₃O₄/rGO

Abstract

While conventional oxides have a high theoretical specific capacity, they also suffer from severe volume expansion during cycling, which seriously affects the stability of the structure. Hence, high‐entropy oxide nanoparticles (Cr0.2Fe0.2Mn0.2Ni0.2Co0.2)3O4, CFMNC) were synthesized and uniformly dispersed on reduced graphene oxide(rGO) carriers using a solvothermal method‐assisted heat treatment as a novel sodium‐ion batteries anode material. The introduction of rGO does not change the crystal structure of CFMNC material, while loading CFMNC into the sheet structure of rGO forms a highly conductive structure, which promotes electron/ion transfer. The high specific surface area is conducive to the full infiltration of the electrode material with the electrolyte, and improve the electrode activity. The random distribution of individual metal ions in CFMNC makes itself have a strong entropy‐driven structural stabilization effect to achieve the cycling stability: 149.1 mAh g−1 can be maintained at 100 mA g−1 over 200 cycles with capacity decay rate of 0.05 % cycle−1. CFMNC/rGO also have excellent rate capability (76.1 mAh g−1at 3000mAg−1, and returned to 153.6 mAh g−1at 200 mA g−1 with almost 100 % capacity retention). Therefore, the composite is considered to offer research potential for the design of high‐performance anode materials through entropy‐driven strategies.