A flexible 3D nitrogen-doped carbon foam@CNTs hybrid hosting TiO_2 nanoparticles as free-standing electrode for ultra-long cycling lithium-ion batteries

摘要

Free-standing electrodes have stood out from the electrode pack, owing to their advantage of abandoning the conventional polymeric binder and conductive agent, thus increasing the specific capacity of lithium-ion batteries. Nevertheless, their practical application is hampered by inferior electrical conductivity and complex manufacturing process. To this end, we report here a facile approach to fabricate a flexible 3D N-doped carbon foam/carbon nanotubes (NCF@CNTs) hybrid to act as the current collector and host scaffold for TiO2 particles, which are integrated into a lightweight free-standing electrode (NCF@CNTs-TiO2). In the resulting architecture, ultra-fine TiO2 nanoparticles are homogeneously anchored in situ into the N-doped NCF@CNTs framework with macro- and meso-porous structure, wrapped by a dense CNT layer, cooperatively enhances the electrode flexibility and forms an interconnected conductive network for electron/ion transport. As a result, the as-prepared NCF@CNTs-TiO2 electrode exhibits excellent lithium storage performance with high specific capacity of 241 mAh g(-1) at 1 C, superb rate capability of 145 mAh g(-1) at 20 C, ultra-long cycling stability with an ultra-low capacity decay of 0.0037% per cycle over 2500 cycles, and excellent thermal stability with similar to 94% capacity retention over 100 cycles at 55 degrees C.