TiO2 Coated with Carbon via Chemical Vapor Deposition as Li-Ion Batteries Anode

With the increasing demand for renewable energy and sustainable technologies, lithium-ion batteries (LIBs) have become crucial energy storage components. Despite the promising properties of the high capacity and stability of TiO2, its large-scale application as an anode for LIBs is hindered by challenges like poor conductivity and volumetric changes during cycling. Here, a rutile TiO2 composite material with a thinned carbon coating (TiO2@TC) was synthesized through chemical vapor deposition (CVD) and a subsequent annealing process, which significantly improved the reversibility, cycling stability, and rate performance of the TiO2 anode materials. The thickness of the carbon layer on TiO2 was precisely controlled and thinned from 4.2 nm to 1.9 nm after secondary annealing treatment, leading to a smaller steric hindrance and an improved conductivity while serving as protective coatings by preventing the electrochemical degradation of the TiO2 surface and hindering volumetric changes during cycling. The resulting TiO2@TC with the thin carbon layer demonstrated a high specific capacity of 167 mAh g−1 at 0.5 C in Li-based half cells, which could stably run for 200 cycles with nearly 100% capacity retention. The thin carbon layer also contributes to an improved rate performance of 90 mAh g−1 at even 20 C. This work provides an innovational strategy for improving the conductivity and volumetric changes during the cycling of TiO2 anodes.