Confining MoSe2 Nanosheets into N-Doped Hollow Porous Carbon Microspheres for Fast-Charged and Long-Life Potassium-Ion Storage

The potassium-ion battery (PIB) is the most promising alternative to a lithium-ion battery (LIB). Exploitation of a suitable electrode material is crucial to promote the development of PIBs. The MoSe2 material has attracted much attention due to its high theoretical capacity, unique layered structure, and good conductivity. However, the potassium storage property of MoSe2 has been suffering from structural fragmentation and sluggish reaction kinetic caused by large potassium ions upon insertion/extraction, which needs to be further improved. Herein, the MoSe2 nanosheets are confined into N-doped hollow porous carbon microspheres (MoSe2@N-HCS) by spray drying and high-temperature selenization. It delivers a superior rate performance of 113.7 mAh g-1 at 10 A g-1 and remains at a high capacity of 158.3 mAh g-1 at 2 A g-1 even after 16 700 cycles for PIBs. The excellent electrochemical performance can be attributed to unique structure, N-doping, and robust chemical bonds. The storage mechanism of MoSe2 for potassium ions was explored. The outstanding properties of MoSe2@N-HCS make it a promising anode material for PIBs.