Preparation of a multifunctional P-CF@Mn3O4 composite as a structural anode material

Abstract

The new energy industry has increasingly higher requirements for the lightweight design and functional integration of the power energy system. As an effective solution to achieve this demand, a structural energy storage integrated composite was prepared that consists of a functional body with an ideal specific capacity combined with considerable mechanical properties. In this study, we prepared a CF@Mn₃O₄ composite by compounding polyacrylonitrile (PAN)-based carbon fiber (CF) with Mn₃O₄ through the three-step method of acid leaching activation, hydrothermal stirring, and high temperature annealing. As a result, the CF@Mn₃O₄ composite maintains a specific capacity of 610.5 mA h g⁻¹ after 150 cycles at the current density of 100 mA g⁻¹, which is approximately 2.48 times higher than that of the carbon fiber. The tensile strength, Young's modulus, and elongation of the CF@Mn₃O₄ composite reached 92.1%, 94.5%, and 93.5% of the original carbon fiber. These significant mechanical and electrochemical characteristics can be attributed to the synergistic effect of the carbon fiber substrate and Mn₃O₄. The carbon fiber served as a buffer substrate to relieve the volume expansion of the deposited layer during the charging and discharging processes, and the Mn₃O₄ was used as a coating layer to provide more insertion sites for lithium ions, which enables a higher charge–discharge specific capacity.