Ni-encapsulated TiO₂ nanotube array prepared using atomic layer deposition as a high-performance Li-ion battery anode

TiO₂-based anodes are highly desired because of their significant safety with good structural stability during charge/discharge. However, the intrinsic poor conductivity of TiO₂ restricts its capacity cycling at a high rate. Herein, we present a good rate-performance anode consisting of Ni-encapsulated TiO₂ nanotube array growing on three-dimensional Ni scaffold. By using atomic layer deposition (ALD), a TiO₂ layer was coated onto Ni nanotubes which were fabricated using ZnO nanorod array template. The Ni-encapsulated TiO₂ nanotube array anode shows a capacity of 188 mAh g⁻¹ after 100 cycles at 0.5 C. The metal Ni encapsulated in the TiO₂ nanotubes provides an efficient pathway for rapid electron transfer. It is believed that the metal-encapsulated composite design presented here would be significant for many possible anodes and cathodes.