Nanoengineering to Achieve High Sodium Storage: A Case Study of Carbon Coated Hierarchical Nanoporous TiO2Microfibers

Abstract

Nanoengineering of electrode materials can directly facilitate sodium ion accessibility and transport, thus enhancing electrochemical performance in sodium ion batteries. Here, highly sodium-accessible carbon coated nanoporous TiO2microfibers have been synthesised via the facile electrospinning technique which can deliver an enhanced capacity of ≈167 mAh g−1after 450 cycles at current density of 50 mA g−1and retain a capacity of ≈71 mAh g−1at the high current rate of 1 A g−1. With the benefits of their porous structure, thin TiO2inner walls, and the introduction of conductive carbon, the nanoporous TiO2/C microfibers exhibit high ion accessibility, fast Na ion transport, and fast electron transport, thereby leading to the excellent Na-storage properties presented here. Nanostructuring is proven to be a fruitful strategy that can alleviate the reliance on materials' intrinsic nature; and the electrospinning technique is versatile and cost-effective for the fabrication of such an effective nanoporous microfiber structure.