Designing advanced sandwiched 2D NC/MoSe2@N-doped carbon arrays as new anode materials for efficient sodium storage

Abstract The rational design and assembly specific structures consisting of multiple components with distinctive features are promising strategies for developing advanced materials for efficient sodium storage. Herein, a novel hierarchical sandwich-liked structure MoSe2 nanosheet array is designed and synthesized, in which MoSe2 nanosheet through strong interfacial interaction is encapsulated in two dimensional carbon framework that improves electrical conductivity and Na+ diffusion kinetic. Moreover, the carbon protective layer reinforces the stability of structure and maintains electrochemical activity during long-term charging/discharging process. The density functional theory calculation (DFT) further confirms carbon incorporation can reduce Na+ diffusion energy barrier for enhancing the reaction kinetics. With the obtained NC/MoSe2@NC as free-standing electrodes for SIBs, it achieves a reversible capacity of 632 mAh g−1 at 0.2 A g−1, or actual capacity of 421 mAh g−1 by removing contributed capacity of the carbon cloth substrate, and excellent long cycling stability. By matching with Na3V2(PO4)3/C cathode, the sodium full cell displays a high energy density of 186.2 Wh kg−1 with a power density of 121.2 W kg−1. This current design and fabrication strategy manifests promising prospect for exploring efficient electrode materials for sodium storage.