Rational design of MoSe2 nanosheet-coated MOF-derived N-doped porous carbon polyhedron for potassium storage

For potassium-ion battery (PIB), it remains a huge challenge to develop an appropriate anode material to compensate the large radius of K+. MoSe2 shows great potential for efficient K+ insertion/extraction due to its unique lamellar structures with an interlayer spacing of 6.46 angstrom. However, pure MoSe2 has low electronic conductivity and agglomerates during long-term cycling. In the present work, MoSe2 nanosheets were fabricated on the N-doped porous carbon polyhedron (NPCP). The obtained product was designated as NPCP@MoSe2 and functioned as anode materials for PIBs. NPCP@MoSe2 displayed a promising reversible capacity (325 mAh/g at 100 mA/g after 80 cycles), long-term cycling performance (128 mAh/g at 500 mA/g after 800 cycles), and superior rate property at 5000 mA/g. The enhanced electrochemical performance of NPCP@MoSe2 could be attributed to the rational design of hybrid structures. Notably, the hollow NPCP provide a large contact area for the interactions among the electrolytes and electroactive materials as well as partly buffer the volume expansion. The synergistic effects between MoSe2 and NPCP could mitigate the agglomeration of MoSe2 nanosheets. Besides, the uniformly doping N elements enhanced the conductivity of the carbon matrix, and the N-group also provided potential binding active sites for K-ion accommodation. This work paves the ideas for the design of novel anode materials with high specific capacity, good cycling stability and outstanding rate capability for PIBs. (C) 2021 Published by Elsevier Inc.

Automated summary

In this study, MoSe2 nanosheets were fabricated on N-doped porous carbon polyhedron (NPCP) to serve as novel anode materials for potassium-ion batteries (PIBs). The hybrid structure of NPCP@MoSe2 exhibited enhanced electrochemical performance with high specific capacity, good cycling stability, and outstanding rate capability.