Topological Insulator‐Assisted MoSe<sub>2</sub>/Bi<sub>2</sub>Se<sub>3</sub> Heterostructure: Achieving Fast Reaction Kinetics Toward High Rate Sodium‐Ion Batteries
Yu Li, Manshu Han, Z. C. Zhou, Xinhui Xia, Qingguo Chen, Minghua Chen
Abstract
Abstract Owing to the large interlayer spacing and the excellent theoretical capacity of MoSe 2 , it has great potential to be applied as an anode material for sodium‐ion batteries. However, the rate performance of MoSe 2 is strongly limited by the insufficient intrinsic electron transfer kinetics. Herein, a simple two‐step hydrothermal method to construct MoSe 2 /Bi 2 Se 3 heterostructures was developed by growing MoSe 2 nanosheets onto Bi 2 Se 3 nanoflakes directly. The typical topological insulator possesses ultrafast surface electronic conductivity, which makes the batteries exhibit a superior rate capability and considerable cycling stability. At a high rate of 10 A g −1 , the MoSe 2 /Bi 2 Se 3 electrode still delivered a superior capacity of 244 mA h g −1 (about 60 % of the discharge capacity at 0.1 A g −1 ), which is better than that in some of the previously reported MoSe 2 /carbon composites. It also can compare with some of the MoSe 2 ‐containing complex sandwich architectures. Such unique rate performance is bound strongly with high interlayer spacing and rapid electron transfer kinetics. Besides, the different Fermi level energies of Bi 2 Se 3 (work function is 5.61 eV) and MoSe 2 (work function is 4.3 eV) probably induce a built‐in electric field nearby the heterofaces. The electric force could promote Na ions diffusibility upon cycling, leading to high reversible capacity and excellent rate performance.