Discharged Titanium Oxide Nanotube Arrays Coated with Ni as a High-Performance Lithium Battery Electrode Material

Transition metal oxides are in high demand as electrode materials for alkali metal-ion batteries due to high theoretical capacity. However, low electron transfer kinetics and slow ion migration lead to poor cycle stability and rate performance of the transition metal oxide electrode. Herein, TiO2 nanotube arrays coated with Ni (Ni/TiO2NTs) are fabricated by using predischarge-electrodeposition method and subsequent calcination under H-2/N-2. In the Ni/TiO2NTs composite, TiO2NTs and Ni nanoparticles play the role of framework and coating layer, respectively. The as-prepared Ni/TiO2NTs composites have a high specific surface area and a unique tubular structure, which facilitates the quick penetration of the electrolyte into the tubes and reduces the lithium ions' diffusion distance. The incorporation of Ti3+ and metallic nickel in the hydrogenated TiO2NTs also increases conductivity. Besides, the spin-polarized surface capacitance of Ni-0 nanoparticles causes the magnetic changes that generate an extra lithium-ion storage capacity. The Ni/TiO2NTs composite electrode maintains a high capacity of 507 mA h g(-1) after 100 cycles at 0.2 A g(-1). Here, the predischarge-electrodeposition provides a new route for the preparation of composite materials.