Carbon-coated Magnéli-phase TinO2n−1 nanobelts as anodes for Li-ion batteries and hybrid electrochemical cells

Abstract

We describe a method for preparing carbon-coated Ti9O17 nanowires using H2Ti3O7 nanobelts as precursors to react with ethane and hydrogen at high-temperature. The carbon-coating layers play a key role in restraining the sintering growth of the core during the phase transformation from H2Ti3O7 to Magnéli-phase TinO2n−1, and in retaining the morphology of nanobelts. We demonstrated that the initial reversible capacity of these Ti9O17 nanobelts attained 182 mA h g−1, a value even higher than the theoretical value of a-TiO2 (167 mA h g−1). Cyclic-voltammetry measurement supports the pseudocapacitive lithium-storage behavior of these Magnéli-phase Ti9O17 nanobelts. Furthermore, the nanobelts exhibit high power density along with excellent cycling stability in their application as hybrid electrochemical cells.