Hierarchical TiO₂-B nanowire@α-Fe₂O₃ nanothorn core-branch arrays as superior electrodes for lithium-ion microbatteries

This paper reports a simple yet efficient method for the synthesis of hierarchical TiO₂-B nanowire@α-Fe₂O₃ nanothorn core-branch arrays based on a stepwise hydrothermal approach. The as-fabricated hybrid arrays show impressive performance as a high-capacity anode for lithium-ion batteries. The key design in this study is a core-branch hybrid architecture, which not only provides large surface active sites for lithium ion insertion/extraction, but also enables fast charge transport owing to the reduced diffusion paths for both electrons and lithium ions. The peculiar combination of attributes of TiO₂ (good structural stability) and Fe₂O₃ (large specific capacity) provides the hybrid array electrodes with several desirable electrochemical features: large reversible capacity (~800 mA·h·g^–1 for specific mass capacity and ~750 μA·h·cm^–2 for specific areal capacity), good cycling stability, and high rate capability. The impressive electrochemical performance, together with the facile synthesis procedure, may provide an efficient platform to integrate the TiO₂ nanowire@Fe₂O₃ nanothorn core-branch arrays as a three-dimensional thin film electrode for lithium-ion microbatteries.