High entropy spinel oxides (CrFeMnNiCox)3O4 (x = 2, 3, 4) nanoparticles as anode material towards electrochemical properties

Abstract

The newly discovered inorganic material termed “high-entropy oxides” (HEOs) nanoparticles are made up of diverse metal elements and possesses a single-phase structure. HEOs nanoparticles exhibit numerous advantageous features, including high specific capacity, exceptional cycling performance, remarkable structural stability, and super electronic conductivity. Consequently, HEOs nanoparticles have garnered attention for their potential as electrode materials for lithium-ion batteries (LIBs). It is essential to develop HEOs utilizing a range of component-metal elements and thoroughly explore their properties. Transition metal oxides that contain Co have exhibited exceptional electrochemical performance. However, high entropy oxides nanoparticles have the potential to exceed the electrochemical performance of other materials by combining different components. Therefore, to leverage the “cocktail effect” of high entropy materials, we increased the Co content in high entropy oxides and synthesized three sets of high entropy spinel oxides (CrFeMnNiCox)3O4 (x = 2, 3, 4) nanoparticles using the solution combustion method. The results show that the three obtained samples have uniform particle size distribution. The reversible capacities at 200 mA·g−1 for (CrFeMnNiCo2)3O4, (CrFeMnNiCo3)3O4 and (CrFeMnNiCo4)3O4 anodes are 467.8 mAh·g−1, 574.1 mAh·g−1 and 506.2 mAh·g−1, respectively. With an increase in the current density, the three sets of samples show gradual changes in their capacities. The high entropy oxides (HEOs) nanoparticles exhibit exceptional cycle stability and rate capability when used as the anode of LIBs. This study proposes a novel approach to create high-entropy energy storage materials, opening up possibilities for future material design.