TiO2(B) as a promising high potential negative electrode for large-size lithium-ion batteries

Needle-like TiO2(B) powder was obtained from K2Ti4O9 precursor by ion exchange to protons, followed by dehydration. The charge and discharge characteristics of the TiO2(B) powder were investigated as a high potential negative electrode in lithium-ion batteries. It had a high discharge capacity of 200–250 mAh g−1 at around 1.6 V vs. Li/Li+, which was comparable with that of TiO2(B) nanowires and nanotubes prepared via a hydrothermal reaction in alkaline solution. It showed very good cycleability, and gave a discharge capacity of 170 mAh g−1 even in the 650th cycle. It also had a high rate capability, and gave a discharge capacity of 106 mAh g−1 even at 10 °C.In most of ethylene carbonate-based solutions, the TiO2(B) powder exhibited good charge and discharge characteristics. However, it showed a poor compatibility with LiBF4, propylene carbonate, and γ-butyrolactone. The TiO2(B) powder showed good cycle performance in the presence of a non-flammable additive, trimethyl phosphate, up to 20 vol.%, and a high tolerance to water up to 1000 ppm. It was also found that inexpensive Al foil can be used as a current collector of the TiO2(B) powder instead of Cu foil without sacrificing the performance.