Synergistic S-doped biomass carbon and N-doped carbon for construction of interlayer expanded MoS2 core/shell nanospheres for potassium and sodium storage

Abstract

The construction of high-performance anode materials is the critical technology for promoting the development and application for potassium-ion batteries (PIBs). Herein, we present the synthesis of S-doped biomass carbon/MoS2@N-doped carbon core-shell nanospheres with the expanded interlayer of 0.99 nm (S-BC/E-MoS2@N-C) via the combined hydrothermal and polymerized method. In the hydrothermal process, we firstly find that the biomass carbon is heteroatomic doped with sulfur in the hydrothermal process by the sulfur source for forming MoS2. The polymerized N-doped carbon is forming on surface of MoS2 nanosheets for construction sandwiched core-shell structure. The N-doped carbon layer and S-doped biomass carbon use cooperatively to establish an omnibearing conductive network on MoS2 by internal and external integration. In such a unique structure, high conductivity and excellent structural stability are achieved in the S-BC/E-MoS2@N-C composite. Consequently, the S-BC/E-MoS2@N-C electrodes exhibit superior potassium storage performances including enhanced rate capability and good cycled stability with high reversible capacities (156.6 mA h g−1 after 650 cycles at 100 mA g−1). And for sodium ion batteries, the S-BC/E-MoS2@N-C electrode delivers an initial reversible capacity of 538.9 mAh g−1 at 200 mA g−1 and maintains 371.1 mAh g−1 after 200 cycles. This work shed a kind of double heteratomic doping and core-shell hierarchical structure of MoS2 anodes in potassium/sodium storage.