Electrospun Coal Liquefaction Residues/Polyacrylonitrile\nComposite Carbon Nanofiber Nonwoven Fabrics as High-Performance Electrodes\nfor Lithium/Potassium Batteries

Abstract

Coal liquefaction\nresidues (CLRs)-based nanofiber nonwoven fabrics are fabricated by\nelectrospinning using the mixture of polyacrylonitrile and preasphaltene\n(toluene insoluble-tetrahydrofuran soluble) as the precursor. CLR-based\ncarbon nanofiber (CF) nonwoven fabrics are further obtained by nitric\nacid pre-oxidization and step-mattered heat treatment. The electrochemical\nperformances of the CF nonwoven fabrics as lithium/potassium-ion battery\n(KIB) electrodes are studied. For lithium-ion batteries, the reversible\ncapacity of CF nonwoven fabric electrodes exhibits as high as 294\nmA h g^–1 after 200 cycles (0.2 A g^–1). For KIBs, it can deliver an impressive rate (103 mA h g^–1 at 1 A g^–1) and discernible cycling performance\nwith a capacity retention of 98% even after 320 cycles. The improved\nelectrochemical performance mainly originates from the unique structure,\nthat is, three-dimensional conductive network, turbostratic structure,\nco-existence of heteroatoms, and short diffusion path. Meanwhile,\nthe successful upgrade of CLR into high-valued CLR-based CF nonwoven\nfabric electrodes for energy storage devices provides a new approach\nto alleviate the reliance on the fossil fuels.