Rapid construction of surface CuO-rich Co3O4/CuO composites as anodes for high-performance lithium-ion batteries

Abstract

We report a facile strategy to produce Co3O4/CuO composites with a similar core-shell structure. Using Metal Organic Framework (MOF) as the precursor, the surface enrichment of cations during calcination is used to tune the CuO to the surface of the composites. The composite consists of a host of Co3O4-rich particles (<50 ​nm) and a surface of CuO-rich nanoparticles (10 ​nm). Among the derivatives, the Co3O4/CuO obtained by pyrolysis at 700 ​°C exhibits the best electrochemical performance (a reversible capacity of 1382 mAh g−1 at 100 ​mA ​g−1) as anodes for lithium-ion batteries (LIBs). The multi-phase synergistic effect solves the cycle problem caused by volume expansion and enables it to obtain stable cycle performance (801.6 mAh g−1 at high density after 250 cycles). Electrochemical analysis results show that the special surface structure is beneficial to obtain low charge transfer resistance and fast ion diffusion rate, while also increasing the surface capacitance behavior during the reaction. Based on the principle of surface enrichment of cations in metal oxide mixtures, it is versatile and easy to prepare special core-shell-like structural materials by a simple calcination method. The excellent surface properties of the Co3O4/CuO composites have a wide practical and potential applications in various fields.