Carbon Nanotube Modified V2O5 Porous Microspheres as Cathodes for High-Performance Lithium-Ion Batteries

For the first time, V2O5/carbon nanotube (CNT) porous microspheres (VCMs) constructed from V2O5 particles homogenously wrapped in highly conductive CNTs have been synthesized through a facile spray-drying route by using commercial V2O5 and CNTs as starting materials. Compared with bare commercial V2O5 particles, the electrochemical performance of VCM is significantly enhanced: it exhibits a large specific capacity of 242.3 mAhg(-1), which is about 69% higher than that of bare commercial V2O5 (145.4 mAhg(-1)); the capacity remains 223.8 mAhg(-1) at 0.2C (1C=294 mAhg(-1)) after 80 cycles with a high capacity retention of 92.3%. The C-rate capacities at 1, 2, 5, and 10 C are 180.8, 154.1, 134.8, and 109.3 mAhg(-1), respectively; these values indicate excellent rate performance. The remarkable performance enhancement is attributed to the interconnected network of conductive CNTs, which guarantees high conductivity and enables fast electron transport between CNTs and V2O5 of the uniformly dispersed VCM. Moreover, VCM provides a hierarchical template to accommodate the structural degradation and delamination of V2O5 particles during electrochemical cycling. The proposed spray-drying strategy is facile, effective, and easy to realize on a large scale for the low-cost industrial production of V2O5/CNT composite cathodes, which can be extended to produce other high-capacity electrode materials with large volume variations and low electrical conductivities.