Electrospun Coal Liquefaction Residues/Polyacrylonitrile Composite Carbon Nanofiber Nonwoven Fabrics as High-Performance Electrodes for Lithium/Potassium Batteries

Coal liquefaction residues (CLRs)-based nanofiber nonwoven fabrics are fabricated by electrospinning using the mixture of polyacrylonitrile and preasphaltene (toluene insoluble-tetrahydrofuran soluble) as the precursor. CLR-based carbon nanofiber (CF) nonwoven fabrics are further obtained by nitric acid pre-oxidization and step-mattered heat treatment. The electrochemical performances of the CF nonwoven fabrics as lithium/potassium-ion battery (KIB) electrodes are studied. For lithium-ion batteries, the reversible capacity of CF nonwoven fabric electrodes exhibits as high as 294 mA 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 with a capacity retention of 98% even after 320 cycles. The improved electrochemical performance mainly originates from the unique structure, that is, three-dimensional conductive network, turbostratic structure, co-existence of heteroatoms, and short diffusion path. Meanwhile, the successful upgrade of CLR into high-valued CLR-based CF nonwoven fabric electrodes for energy storage devices provides a new approach to alleviate the reliance on the fossil fuels.