In situ heterogeneous interface construction boosting fast ion/electron transfer for high-performances lithium/potassium storage

Molybdenum diselenide (MoSe2) materials have aroused great attention for Li/K storage due to its high theoretical capacity and low cost. However, MoSe2 often suffer from poor rate performances and unsatisfied cyclability for Li/K storage due to sluggish kinetics and the structure collapse upon cycling. Herein, a MoSe2-SnS heterostructure, SnS nanoparticles anchored at MoSe2-graphene matrix (SnS@MoSe2-GR), was constructed to improve rate performances and cyclability for Li/K storage. The heterointerfaces between MoSe2 and SnS can generate unbalance charge distribution and thus induce an interfacial electric-field within the interfaces, which could accelerate charge-transfer kinetics and improve surface reaction kinetics. As a result, SnS@MoSe2-GR exhibit excellent electrochemical performances for Li/K storage. The electrochemical storage mechanisms of SnS@MoSe2-GR have been investigated by in situ and ex situ characterizations, and DFT calculations. Furthermore, the SnS@MoSe2-GR and porous carbon were used as anodes and cathodes to construct K-ion capacitors (KICs), the KICs exhibit an excellent rate performance, outstanding discharge capability and satisfied life-span (a high capacity retention of 93.3% after 5000 cycles). Our work provides new insights and understanding for the development of MoSe2 based-anodes with high-performance and long-lifespan for Li/K storage.

Automated summary

In this study, a MoSe2-SnS heterostructure material was constructed to improve rate performance and cyclability for Li/K storage through the electric-field effect generated by heterointerfaces accelerating charge transfer kinetics. When used to construct K-ion capacitors, the material exhibited outstanding performance and long lifespan.