Amorphous carbon intercalated MoS2 nanosheets embedded on reduced graphene oxide for excellent high‐rate and ultralong cycling sodium storage

Abstract

Abstract MoS2 as a typical layered transition metal dichalcogenide (LTMD) has attracted considerable attention to work as sodium host materials for sodium‐ion batteries (SIBs). However, it suffers from low semiconducting behavior and high Na+ diffusion barriers. Herein, intercalation of N‐doped amorphous carbon (NAC) into each interlayer of the tiny MoS2 nanosheets embedded on rGO conductive network is achieved, resulting in formation of rGO@MoS2/NAC hierarchy with interoverlapped MoS2/NAC superlattices for high‐performance SIBs. Attributed to intercalation of NAC, the resulting MoS2/NAC superlattices with wide MoS2 interlayer of 1.02 nm facilitates rapid Na+ insertion/extraction and accelerates reaction kinetics. Theoretical calculations uncover that the MoS2/NAC superlattices are beneficial for enhanced electron transport, decreased Na+ diffusion barrier and improved Na+ adsorption energy. The rGO@MoS2/NAC anode presents significantly improved high‐rate capabilities of 228, 207, and 166 mAh g−1 at 20, 30, and 50 A g−1, respectively, compared with two control samples of pristine MoS2 and MoS2/NAC counterparts. Excellent long‐term cyclability over 10 000 cycles with extremely low capacity decay is demonstrated at high current densities of 20 and 50 A g−1. Sodium‐ion full cells based on the rGO@MoS2/NAC anode are also demonstrated, yielding decent cycling stability of 200 cycles at 5C. Our work provides a novel interlayer strategy to regulate electron/Na+ transport for fast‐charging SIBs.

Keywords

• carbon intercalation
• electronic regulation
• interlayer expansion
• MoS2
• sodium storage