Conformal coating of TiO2 nanorods on a 3-D CNT scaffold by using a CNT film as a nanoreactor: a free-standing and binder-free Li-ion anode

A free-standing and binder-free electrode, which consists of a 3-D conductive scaffold and conformal TiO2 nanorods, is synthesized by using an interconnected CNT film as a nanoreactor. Such a conformal 3-D nanostructure can not only provide the electrodes with fast charge transportation and long-term structural integrity, but also eliminate the heavy metal current collector, polymer binder and conductive additive. The conformal CNT-TiO2 anode demonstrates exceptional electrochemical properties with high capacity, high rate capability and excellent cycling stability. It shows a charge capacity of 129 mA h g(-1) after 1000 cycles at 10 C with a low capacity fade of 0.007% per cycle in a half cell. Meanwhile, the CNT-TiO2/LiFePO4 full cell exhibits superior capacity retention with a high Coulombic efficiency of approximately 100% during 400 cycles at 2 C. Such a 3-D conformal nanostructure is promising for application in high-performance energy storage.