Nitrogen-doped/carbon-coated 2D TiO2 Scaly clusters as high-performance anode for Lithium-ion batteries

Abstract

TiO2 has been considered as a promising anode material for lithium-ion batteries (LIBs) due to its low cost and high stability, but its low conductivity has greatly limited its application. In this study, the nitrogen-doped TiO2 (N-TiO2) with a uniform carbon coating was prepared by the solvothermal method. According the XPS results, the nitrogen was successfully doped in the TiO2. The N-doped TiO2 electrode exhibited obviously higher lithium-ion storage performance, of which the discharge capacity was 420 mAh g−1 under the current density 0.1 A g−1. Additionally, the superior long-term cycling stability was also observed with a reversible capacity of 148 mAh g−1 after 3000 cycles under 3 A g−1 current density. The result showed that after the nitrogen doped, the replacing of lattice oxygen with nitrogen can decrease the band-gap width and improve the conductivity of titanium oxide. Meanwhile, the oxygen vacancies on the surface of the material can adsorb a large number of lithium ions and produce significant pseudo-capacitance, thus, effectively increasing the specific capacity of the material. Therefore, the N-doped TiO2 electrode can present obviously higher lithium-ion storage performance.