Pseudocapacitance-Enhanced Li-Ion Microbatteries Derived by a TiN@TiO2 Nanowire Anode

Summary Titanium dioxide (TiO 2 ) has been studied extensively as a stable, cheap, and safe anode material for Li-ion batteries. However, the inherent sluggish Li-ion diffusion and particularly poor electronic conductivity limit its practical applications. Here, we report a core/shell TiN/TiO 2 nanowire array to tackle these problems. The single-crystal-like TiN nanowire cores function as highly conductive nanostructured current collectors, and the branched shell is constructed by nanoporous anatase TiO 2 mesocrystals. This 3D nanoarray electrode exhibits a pseudocapacitity-dominated charge storage of lithium ions with outstanding performance in terms of high areal and volumetric capacity, fast charge-discharge ability, and long cycling lifetime. Charge transport through the unique nanoporous TiO 2 mesocrystal shells and the high-conductivity TiN nanowire core account for the superior performance.