Hydrothermal synthesis of Li_4-xNa_xTi₅O₁₂ and Li_4-xNa_xTi₅O₁₂/graphene composites as anode materials for lithium-ion batteries

School of Materials Science and Engineering, Hefei University of Technology, Hefei, Anhui 230009, China

^* Corresponding author: Ji-ping ZHU; Tel:18919665197; E-mail: jpzh@ustc.edu.cn

Abstract

A potential Lithium-ion battery anode material Li_4-xNa_xTi₅O₁₂ (0≤x≤0.15) has been synthesized via a facile hydrothermal method with short processing time and low temperature. The XRD and FE-SEM results indicate that samples with Na-doped are well-crystallized and have more homogeneous particle distributions with smaller overall particle size in the range of 300-600nm. Electrochemical tests reveal that Na-doped samples exhibit impressive specific capacity and cycle stability compared to pristine Li₄Ti₅O₁₂ at high rate. The Li_3.9Na_0.1Ti₅O₁₂ electrode deliver an initial specific discharge capacity of 169mAh/g at 0.5C and maintained at 150.4mAh/g even after 40 cycles with the reversible retention of 88.99%. Finally, a simple solvothermal reduction method was used to fabricate Li_3.9Na_0.1Ti₅O₁₂/graphene(Li_3.9Na_0.1Ti₅O₁₂/G) composite. Galvanostatic charge-discharge tests demonstrate that this sample has remarkable capacities of 197.4mAh/g and 175.5mAh/g at 0.2C and 0.5C rate, respectively. This indicates that the Li_3.9Na_0.1Ti₅O₁₂/G composite is a promising anode material for using in lithium-ion batteries.