Air-stabilized pore structure engineering of antimony-based anode by electrospinning for potassium ion batteries

Due to the large ionic radius and associated slow reaction kinetics of potassium ions, it is a major challenge to find suitable anode materials for potassium-ion batteries. Herein, we design porous antimony-based nanofibres via a simple, low-cost and large scalable method to promote the electrochemical performance of potassium-ion batteries. Unlike those traditionally treated in inert atmospheres, using the different decomposition processes of polyacrylonitrile and polyvinylpyrrolidone in air, we obtain antimony trioxide embedded in porous carbon nanofibres (Sb₂O₃@PCN). The porous structure can promote the permeation of electrolyte into electrode materials and increase the active sites of the redox reaction. The porous carbonaceous fibre skeleton structure establishes a fast ion transport channel and enhances the kinetic performance. In a concentrated 5 M potassium bis(fluorosulfonyl)-imide/dimethyl carbonate electrolyte, Sb₂O₃@PCN exhibits a stable discharge specific capacity of 437.3 mAh g^-1 at a current density of 100 mA g^-1 after 50 cycles, which is much higher than that treated in a N₂ atmosphere (247.5 mAh g^-1). This method provides a new approach for the preparation of efficient potassium-ion battery electrode materials.