Template-Based Engineering of Carbon-Doped Co₃O₄ Hollow Nanofibers as Anode Materials for Lithium-Ion Batteries

Co₃O₄ anode materials exhibit poor conductivity and a large volume change, rendering controlling of their nanostructure essential to optimize their lithium storage performance. Carbon-doped Co₃O₄ hollow nanofibers (C-doped Co₃O₄ HNFs), for the first time are synthesized using bifunctional polymeric nanofibers as template and carbon source. Compared with undoped Co₃O₄ HNFs and solid Co₃O₄ NFs, C-doped Co₃O₄ HNFs feature a remarkably high specific capacity, excellent cycling stability, and superior rate capacity as anode materials for lithium-ion batteries. The superior performance of C-doped Co₃O₄ HNFs electrodes can be attributed to their structural features, which confer enhanced electron transportation and Li⁺ ion diffusion due to C-doping, and tolerance for volume change due to the 1D hollow structure. Density functional theory calculations provide a good explanation of the observed enhanced conductivity in C-doped Co₃O₄ HNFs. Carbon-doped Co₃O₄ hollow nanofibers are synthesized, displaying excellent Li⁺ ion storage properties including high specific capacity, long-term cycling stability, and outstanding rate capacity. Density functional theory calculations reveal a larger delocalization of the band structure as being responsible for the enhanced conductivity observed.