Deep insights into kinetics and structural evolution of nitrogen-doped carbon coated TiNb24O62 nanowires as high-performance lithium container.

Abstract TiNb 24 O 62 with large theoretical capacity and safe working potential is regarded as a candidate for lithium ion batteries. However, poor electronic conductivity of TiNb 24 O 62 restricts its widely application. Herein, we propose a novel methodology concerned about nitrogen-doped carbon coating to improve the electrochemical performance of TiNb 24 O 62 nanowires. According to a series of analyses, it is found that nitrogen-doped carbon coating plays a key role on improving the electronic conductivity and electrochemical activity of TiNb 24 O 62 nanowires. Meanwhile, both first principles calculations and in-situ XRD technique are applied to realize the structural evolution of nitrogen-doped carbon coated TiNb 24 O 62 nanowires. The obtained results show a high diffusion channel for lithium ions in the lattice of TiNb 24 O 62 and the good electrochemical reversibility of nitrogen-doped carbon coated TiNb 24 O 62 nanowires. In addition, a full lithium ion battery is assembled by using nitrogen-doped carbon coated TiNb 24 O 62 nanowires as anode and LiFePO 4 as cathode. Such a cell can deliver a high capacity, indicative of a great potential for practical applications. Therefore, nitrogen-doped carbon coated TiNb 24 O 62 nanowires can be a promising anode for high-rate lithium ion batteries. Graphical abstract fx1 Highlights • TiNb 24 O 62 nanowires are prepared by an electrospinning method. • Nitrogen-doped carbon is coated on TiNb 24 O 62 nanowires via a novel method. • A reversible capacity of 148.9 mA h g⁻¹ can be delivered after 900 cycles at 10 C. • First principles calculations are adopted to realize the lithium storage mechanism. • Structural evolution of TiNb 24 O 62 /NC upon cycling is analyzed by in situ XRD. [ABSTRACT FROM AUTHOR]