Hierarchical chrysanthemum-like MoS2/Sb heterostructure encapsulated into N-doped graphene framework for superior potassium-ion storage

Abstract

Although potassium-ion batteries (PIBs) have received increasing attentions in the large-scale energy storage application own to its natural abundance of potassium resources, the sluggish reaction kinetics and inferior structure endurability of host materials severely restrict the PIBs development. Herein, we rationally design an exquisite hierarchical MoS2/Sb heterostructure encapsulated into N-doped graphene framework (MS@C) as an advanced anode material for PIBs. Specifically, the evenly distributed Sb nanoparticles are impregnated into the few-layered MoS2 nanosheets, which are further encapsulated by the N-substituted graphene framework, constructing a hierarchical chrysanthemum-like heterostructure. It is noted that this heterostructure can not only effectively prevent the coarsening of alloyed Sb nanograins at the heterointerface, but also serve as the buffer container to alleviate the volume expansion during (de)potassiation process. Moreover, benefitting from the synergistic coupling effect induced between the external nitrogen-doped graphene and internal MoS2/Sb heterostructure, the electron transportation and ions diffusion are aggressively accelerated, promoting the entire electrode conductivity. Consequently, the resulting MS@C composite delivers a high reversible capacity (359.5 mAh g−1 at 0.05 A g−1) and outstanding cycling stability (only capacity loss of 0.027% per cycle during long-term 1000 cycles at high rate of 2 A g−1), demonstrating the robust structural integrity and excellent electrochemical performance. This work provides a promising strategy of composition optimization for delicately designing advanced anode materials, demonstrating the promising in exploring high-quality potassium-ion storage applications.