A flexible free-standing cathode based on graphene-like MoSe2 nanosheets anchored on N-doped carbon nanofibers for rechargeable aluminum-ion batteries

Abstract

Graphene-like MoSe2 nanosheets anchored on N-doped carbon nanofiber (MoSe2@NCNF) composite are prepared and serve as a flexible free-standing cathode material of rechargeable aluminum-ion batteries(AIBs) without any additives or processing procedures. The aluminum storage mechanism of MoSe2 is investigated by ex situ X-ray diffraction, which is evidenced to be that Al3+ intercalates into the MoSe2 lattice related to the interlayer space of (002) plane during the discharge process, and the reversible extraction process occurs during the charge process. The conductive 3D network interlaced by NCNFs facilitates electron transfer and ion diffusion. Furthermore, the MoSe2 nanosheets anchored on the NCNF surface are well-dispersed without aggregation, which results in improved diffusion kinetics and a high utilization rate of the active material for aluminum storage. Profiting from the synergistic effect between active material and carbon template, MoSe2@NCNF cathode achieves a high initial discharge capacity of 296.3 mA h g− 1 at a current density of 100 mA g− 1, even after 200 cycles, the discharge capacity remains stable at 169.9 mA h g− 1 with negligible fading rate. The flexible free-standing composite material with outstanding electrochemical performances may provide new ideas for designing high-performance cathode materials for AIBs and other flexible energy storage devices.