A new spinel high-entropy oxides nanoparticles (FeCoNiMnZn)3O4 as anode materials for lithium-ion batteries

Abstract

A novel (FeCoNiMnZn)3O4 HEO as an anode in lithium-ion batteries (LIBs) was developed for the first time. High-entropy oxide (HEO) of (FeCoNiMnZn)3O4 was synthesized using a hydrothermal technique to control size and crystallinity. We also synthesized oxides of each element (Fe, Co, Ni, Mn, Zn) from HEO composition under similar condition for comparison. The samples were then analyzed using XRD, SEM, TEM, EDS elemental mapping, surface area analysis, ICP-OES, and XPS. Cyclic voltammetry, galvanostatic charge-discharge, electrochemical impedance spectroscopy, and associated coulombic efficiencies were also used to study the electrochemical performance of (FeCoNiMnZn)3O4. Three samples with different preparation conditions, HEO-3, HEO-6, and HEO-9, were selected for investigation. HEO-3 particles are the smallest, 2.95 ± 0.29 nm, and have an irregular shape, making them difficult to measure. In contrast, HEO-6 and HEO-9 particles have diameters between 23.16 ± 7.56 nm and 90.42 ± 3.27 nm, respectively. The HEO-9 performs exceptionally well electrochemically. It exhibits excellent performance of 625.5 mA h g-1 at 1000 mA g-1 and a large capacity of 1333.54 mA h g-1 at 50 mA g-1. After cycling, we also investigated the physical and chemical characterization to identify the change. HEO-9 still has a more stable performance and the least volume change. From these results, developing an anode for lithium-ion batteries (LIBs) in the future looks promising.