Enhancing potassium-ion battery performance by MoS2 coated nitrogen-doped hollow carbon matrix

Abstract

As an important alternative to lithium-ion batteries (LIBs), potassium-ion batteries (PIBs) have attracted much attention due to the abundance and low cost of potassium, however, it is still a great challenge to select suitable anode materials to accommodate the large-size of K-ion. Herein, MoS2 nanosheets were coated on the porous carbon polyhedron derived from zeolite imidazole framework-8 (designated as PCP@MoS2) and employed as the anode materials for PIBs. Benefiting from the high electrical conductivity, strong structure stability of the nitrogen-doped carbon polyhedron and the layered crystal structure of MoS2, the reversible capacity can be maintained at 375 mA h g−1 after 100 cycles at 100 mA g−1, 200 mA h g−1 after 200 cycles at 500 mA g−1 as well as excellent rate property. The excellent electrochemical performance can be attributed to the unique hybrid structures and the synergistic effects between MoS2 and N doped porous carbon polyhedron, which could enhance the electronic conductivity, shorten the K-ion diffusion distance, mitigate the agglomeration of the MoS2 nanosheets, relieve the volume variation, and provide plenty of active sites for K ion accomodation.