Electrochemical energy storage and rectification performance of high-entropy oxide (CrMnFeCoNi)3O4

High-entropy oxides have the advantages of flexible compositional and functional designability, a wide potential window, and high electrical conductivity, which make them show great potential for catalysis and electrochemical energy storage. However, high-entropy oxides are synthesized at high temperatures, which tends to coarsen the grains and agglomerate the particles. In this study, (CrMnFeCoNi)3O4 powders with spinel structure were prepared by the glucose gelation method, and the glucose/metal cation molar ratio (G/M) will affect the final particle size of high-entropy oxide powders. Electrochemical tests demonstrated that as-prepared highentropy oxides powders had a specific capacitance of 491 F g- 1 at a current density of 0.5 A g- 1. HEO/AC asymmetric supercapacitors exhibit a wide voltage window (0-1.6 V) at 0.5 A g- 1 and a specific capacitance of 292.8 F g- 1. An energy density of 104.1 W h kg- 1 was achieved at a power density of 3991.8 W kg- 1. A new discovery is that in addition to the energy storage function, this device also exhibits rectification characteristics similar to semiconductor diodes (RR & Iukcy; = 5.3), which is expected to be applied to electronic circuit components. This work shows that high-entropy oxides can be applied in the field of electrochemical diodes through the controllable preparation of high-entropy oxides, which broadens the application field of high-entropy oxides.