Hierarchical Structured Cu/Ni/TiO 2 Nanocomposites as Electrodes for Lithium-Ion Batteries.

The electrochemical performance of anodes made of transition metal oxides (TMOs) in lithium-ion batteries (LIBs) often suffers from their chemical and mechanical instability. In this research, a novel electrode with a hierarchical current collector for TMO active materials is successfully fabricated. It consists of porous nickel as current collector on a copper substrate. The copper has vertically aligned microchannels. Anatase titanium dioxide (TiO ₂ ) nanoparticles of ∼100 nm are directly synthesized and cast on the porous Ni using a one-step process. Characterization indicates that this electrode exhibits excellent performance in terms of capacity, reliable rate, and long cyclic stability. The maximum insertion coefficient for the reaction product of Li _x TiO ₂ is ∼0.85, a desirable value as an anode of LIBs. Cross-sectional SEM and EDS analysis confirmed the uniform and stable distribution of nanosized TiO ₂ nanoparticles inside the Ni microchannels during cycling. This is due to the synergistic effect of nano-TiO ₂ and the hierarchical Cu/Ni current collector. The advantages of the Cu/Ni/TiO ₂ anode include enhanced activity of electrochemical reactions, shortened lithium ion diffusion pathways, ultrahigh specific surface area, effective accommodation of volume changes of TiO ₂ nanoparticles, and optimized routes for electrons transport.