Ti3+ self-doped Li4Ti5O12 nanosheets as anode materials for high performance lithium ion batteries

Abstract

Ti³⁺ self-doped Li₄Ti₅O₁₂ (S-LTO) nanosheets have been synthesized via a facile solvothermal approach combined with hydrogenation treatment. The thickness and lateral dimension of Li₄Ti₅O₁₂ nanosheets are 10–20 nm and 100–400 nm, respectively. The Ti³⁺ species and/or oxygen vacancies are well introduced into the crystal structures of Li₄Ti₅O₁₂ after hydrogen reduction, resulting into an enhancement in the electronic conductivity and the modified surface electrochemical activity. When evaluated for lithium storage capacity, the S-LTO nanosheets exhibit enhanced electrochemical energy storage performances compared to the pristine Li₄Ti₅O₁₂ (P-LTO) nanosheets, including high capacity (165.6 mA h g⁻¹ at 0.5 C), excellent rate capability (119.6 mA h g⁻¹ at 20 C), and good cyclic stability (95.3% capacity retention after 100 cycles at 10 C). The improvement of lithium storage performances is ascribed to the increased electronic conductivity and the shortened lithium ion diffusion paths arising from the introduction of Ti³⁺ species and the ultrathin thickness of S-LTO.