Lithium storage characteristic of nanoporous high-entropy alloy@high-entropy oxide with spin-dependent synergism of cations

Abstract

High-entropy oxides (HEOs) are a novel class of promising anode materials for lithium-ion batteries, ascribing to their entropy-stabilized structure, regulable electronic structure, and high theoretical capacity. Nevertheless, there still lacks a systematic investigation into the function of HEO owing to the muddled arrangement of multiple elements. Moreover, a proper modification of the electrode microstructure is still needed to render better electrochemical performance. Herein, a nanoporous high-entropy alloy@high-entropy oxide (np-HEA@HEO) composite is synthesized, which possesses a job-sharing structure to separately store electrons and ions. The np-HEA-8@HEO sample with optimized particle size and interconnected mesopores exhibits the best Li storage performance. Lattice distortions and oxygen vacancies in the as-synthesized samples are detected, which are beneficial for rapid Li+ transport. The fast kinetics are verified to be contributed by a large portion of pseudocapacitance. DFT calculations demonstrate reduced d-p band energy difference and spin-dependent synergy of multi-cations in HEO, which can regulate the Li+ adsorption/desorption behavior and promote the reaction kinetics. Our results provide new insights into the features and properties of HEO in terms of Li storage characteristics.