Porous nitrogen-doped FeP/C nanofibers as promising anode for potassium-ion batteries

Potassium-ion batteries (PIBs) are regarded as one of the alternatives to lithium-ion batteries due to the vast potassium reserves in nature and low potential of K + /K. Therefore, in this work, we successfully synthesized porous nitrogen-doped FeP/C nanofibers (P-FeP/C-N NFs), a novel electrode material for PIBs, via simple electrospinning and subsequent calcination treatment, in which polyacrylonitrile (PAN) and polymethylmethacrylate (PMMA) are used as nitrogen source and pore-forming agent, respectively. The introduction of nitrogen improves the conductivity of the material, and the formation of a porous structure increases the specific surface area. More importantly, when the P-FeP/C-N NFs were used as electrode for potassium ion batteries, they exhibit excellent electrochemical performance. The P-FeP/C-N NFs electrode exhibits a discharge capacity of 274.2 mA·h/g at 100 mA/g after 250 cycles and 171.3 mA·h/g at 1000 mA/g after 300 cycles. Even at 5000 mA/g, it displays a high discharge capacity of 150.1 mA·h/g. These findings indicate that the P-FeP/C-N NFs are expected to be a candidate of anode materials for potassium ion batteries.