TiO2/Carbon Nanosheets Derived from Delaminated Ti3C2-MXenes as an Ultralong-Lifespan Anode Material in Lithium-Ion Batteries

Abstract

TiO2–carbon nanosheets (TiO2-C NS) with high electrical conductivity are synthesized by CO2 oxidation of Ti3C2 MXene. Importantly, the synthesized TiO2-C NS (high TiO2 content of 98.45%) can be used without adding a conductive material to impart electrical conductivity. The electrochemical properties show good capacity reversibility at a current density of 2 A g−1 in coin-type half-cells. In particular, a prototype pouch cell of TiO2-C NS//NCM523 also demonstrates that TiO2-C NS as an anode material is a good match with commercial cathode materials for lithium-ion batteries. The good electrochemical performance of TiO2-C NS is attributed to the following factors: 1) the high surface area has abundant exposed active sites offering more Li+ insertion channels and short pathways of the Li+ and electrons; 2) TiO2-C NS has structural stability and low volume expansion (<4%) during Li+ insertion and desertion; and 3) the nanostructure of TiO2-C NS prevents restacking and agglomerating by the surface-anchored TiO2 nanoparticles. The obtained results suggest that TiO2-C NS, wherein TiO2 nanoparticles are densely and homogeneously loaded on both sides of the carbon sheets, are a promising anode material for lithium-ion batteries.