(CrMnCoNiZn)3O4@PPy core-shell nanocomposite with excellent electrochemical performance as lithium-ion battery anode

Abstract

High entropy oxides (HEOs) have an excellent potential for use as electrode materials in lithium-ion batteries (LIBs) due to their high theoretical specific capacity. In this work, spinel-structured (CrMnCoNiZn)3O4 HEO nanoparticles with five elements in equal molar ratio is first generated by solution combustion method. (CrMnCoNiZn)3O4@polypyrrole (PPy) nanocomposites are prepared by in-situ polymerization method. As an anode for lithium-ion batteries, the electrochemical performance of the (CrMnCoNiZn)3O4@PPy composite outperforms that of (CrMnCoNiZn)3O4 nanoparticles. The capacity is 802 mAh/g after 100 cycles at a current density of 100 mA/g, 416 mAh/g after 1000 cycles at a high current density of 1 A/g, and 360 mAh/g rate capacity at 2 A/g. The excellent electrochemical performance of the composites is mainly due to the fact that the conductive and flexible PPy is encapsulated on the high-entropy oxides, which can alleviate the volume change triggered by extraction-insertion of lithium ions process, as well as enhance the electrical conductivity and reduce the occurrence of some side reactions. This method of compositing materials can also be used in other HEOs and conductive polymers, providing a new idea to enhance the electrochemical properties of HEOs.