Ultrafast green microwave-assisted synthesis of high-entropy oxide nanoparticles for Li-ion battery applications

In this study, a novel ultrafast facile green microwave-assisted method was developed for the synthesis of high-entropy oxide (HEO) (Mg, Cu, Ni, Co, Zn)O nanoparticles for the first time. The results indicated that all the five metallic elements were uniformly distributed in the single-phase rocksalt structure of the HEO nanoparticles. The particle-size distribution was within the range of 20–70 nm, with the average size of 44 nm. When used as anode materials for Li-ion batteries, the HEO nanoparticles exhibited remarkable lithium storage properties with the impressive stability as was demonstrated during 1000 cycles at 1 A/g. The exceptional advantages of the proposed method in this work, including ultrafast speed (few minutes), low temperature, nanoscale and high-purity products, and low cost, make it an excellent synthesis technique for application in newly developed high-entropy ceramics, particularly for Li-ion batteries.