Hierarchical nanosheets constructed by integration of bimetallic sulfides into N-Doped carbon: Enhanced diffusion kinetics and cycling stability for sodium storage

Abstract

Transition metal sulfides (TMS) are considered as anode candidates for sodium-ion batteries (SIBs) due to the high theoretical specific capacity and natural abundance. Herein, Co3S4@1T MoS2/NC-L hierarchical nanosheets, in which bimetallic sulfides are integrated into N-doped carbon, has been designed and prepared via calcination of leaf-like Co-ZIF (ZIF-L) precursor followed by hydrothermal sulfuration reaction. When evaluated as anode for SIBs, the Co3S4@1T MoS2/NC-L hierarchical nanosheets offer enhanced pseudocapacitance effect, fast Na+ kinetics in the heterogenous interface of bimetallic sulfides and small polarization, achieving an delightful reversible capacity of 595 mAh g−1 at 0.1 A g−1 and rate capability of 338 mA h g−1 at 5 A g−1. Moreover, the fine structural stability and mutual affinity of bimetallic sulfides under high cutoff voltage hinder the loss of sodium polysulfide during conversion reaction, promoting the long cycling stability of hierarchical nanosheets. Such bimetallic sulfides/N-doped carbon hierarchical nanosheet sheds new light on the construction of efficient anode material for SIBs.