High Rate and Long Cycle Life Anodes via Atomic Layer Deposition of Titanium Dioxide Coatings on Mesoporous Activated Carbon

摘要

As an anode active material for lithium ion (Li-ion) batteries, titanium dioxide (TiO_2) has recently attracted much attention from researchers due to its high theoretical specific capacity, safety characteristics arising from its high electrochemical potential (～1.5V) vs. Li/Li~+, low cost, material availability and environmental benignity. However, the low electronic conductivity, sluggish Li" diffusivity and poor cycle performance of TiO_2 have limited its widespread acceptance in practical rechargeable Li-ion batteries. Here, we present a promising method of preparing TiO_2 based anodes via atomic layer deposition (ALD) coatings of TiO_2 on mesoporous activated carbon (AC) electrodes. TiO_2-AC anodes prepared in this study demonstrated remarkable electrochemical performance with drastically increased specific capacity, extremely high rate capability attributed to facile Li~+ insertion/extraction of ALD coated, nano-sized TiO_2 particles, and excellent cycle performance.