Electrochimica Acta, Vol.309, 242-252, 2019
Synergistic effect of N-doping and rich oxygen vacancies induced by nitrogen plasma endows TiO2 superior sodium storage performance
It is still a great challenge to develop advanced TiO2 anodes for sodium ion batteries (SIBs) owing to its low electronic conductivity and inferior sodium ion diffusion. Structure regulating is a very promising strategy for TiO2. Herein, we propose a novel and facile N-2 plasma assisted annealing strategy, by which nitrogen heteroatoms and rich oxygen vacancies are incorporated into the TiO2 crystal simultaneously, leading to highly enhanced electronic conductivity. In addition, the nitrogen doped and defect-rich TiO2 possesses much higher Brunauer-Emmett-Teller (BET) specific surface area of 92.5 m(2)g(-1) than that (59.9 m(2)g(-1)) of pristine TiO2, resulting in much shorter sodium ion diffusion path. When investigates as a SIBs anode, the modified TiO2 delivers a high reversible capacities of 266 and 129 mAh g(-1) at 50 and 2000 mA g(-1), respectively, and long-term cycling stability with negligible capacity decay at 2000 mA g(-1). As confirmed by the experimental characterizations and density functional theory calculations, the significantly improved electrochemical properties should be attributed to the synergistic effect of nitrogen heteroatoms and rich oxygen vacancies induced by N-2 plasma. This novel N-2 plasma assisted strategy is proved to be highly effective in designing high performance materials in SIBs. (C) 2019 Elsevier Ltd. All rights reserved.