Sandwich-like Co3O4/MXene composites as high capacity electrodes for lithium-ion batteries

Abstract

MXenes have been considered as promising anode materials for lithium-ion batteries (LIBs), owing to their specific surface chemistry, high electron conductivity and large specific surface. However, the low theoretical capacity and restack tendency of layers during the lithiation/delithiation process hinder their further development. In this work, sandwich-like Co₃O₄/Ti₃C₂T_x composites were prepared by a simple ultrasound treatment. In the composites, Co₃O₄ nanoparticles distributed in the interlayers of Ti₃C₂T_x prevent layers from restacking, enhancing the structural stability of the Ti₃C₂T_x matrix in the longitudinal direction. Acting as the substrate, Ti₃C₂T_x not only improves electronic conductivity of the composites but also provides a high specific surface area to load Co₃O₄ nanoparticles. Besides, the lithiation-induced refining architecture enhances reaction kinetics and provides more active sites. In short, the synergistic effect of Co₃O₄ and Ti₃C₂T_x and the effective architecture make the Co₃O₄/Ti₃C₂T_x composite with a Co₃O₄ content of 50% (Co₃O₄/Ti₃C₂T_x-3) exhibit remarkable performance. The capacity of Co₃O₄/Ti₃C₂T_x-3 remains at 999.3 mA h g⁻¹ after 900 cycles at a current density of 500 mA g⁻¹.