writer：Xuebo Zhao, Chunliu Yan, Xin Gu, Liangjun Li, Pengcheng Dai, Dawei Li and Hongyu Zhang
keywords：TiO2,N-Doped Porous Carbon,Sodium-Ion Batteries
source：期刊
specific source：Chemelectrochem, 2017,4,6,1516-1522
Issue time：2017年
TiO2-based nanocomposites with rationally designed size, structure, and composition are highly desirable for Na-ion storage. In this work, various TiO2/N-doped porous carbon nanocomposites (TiO2/NC) have been fabricated by directly carbonizing NH2-MIL-125(Ti) at different temperatures. These TiO2/NC nanocomposites exhibit unique structure features, such as ultrafine TiO2 nanoparticles, micro-mesoporous structure, and N-doped carbon coating, which can shorten the Na-ion diffusion distance, enhance the electronic conductivity, and prevent nano-sized TiO2 from aggregation. When applied as sodium-ion battery anodes, TiO2/NC-600 exhibits the best sodium storage properties among the TiO2/NC nanocomposites produced at different carbonization temperatures. Correlations between electrochemical properties and size/structure/composition of the TiO2/NC nanocomposites are disclosed. TiO2/NC-600 delivers a high reversible capacity of 190?mA?h?g?1 for up to 500 cycles at 1?C (1?C=335?mA?g?1), an ultrahigh capacity of 76?mA?h?g?1 at a high rate of 20?C, and an excellent long-term cycling stability with a capacity of 159?mA?h?g?1 retained after 2500 cycles at 5?C. The outstanding sodium storage performance of TiO2/NC-600 is attributed to an appropriate crystalline structure, particle size, and high nitrogen-doping content.