Pseudocapacitive Potassium‐Ion Intercalation Enabled by Topologically Defective Soft Carbon toward High‐Rate, Large‐Areal‐Capacity, and Low‐Temperature Potassium‐Ion Batteries

Abstract

Abstract Carbonaceous materials are widely investigated as anodes for potassium‐ion batteries (PIBs). However, the inferior rate capability, low areal capacity, and limited working temperature caused by sluggish K‐ions diffusion kinetics are still primary challenges for carbon‐based anodes. Herein, a simple temperature‐programmed co‐pyrolysis strategy is proposed for the efficient synthesis of topologically defective soft carbon (TDSC) based on inexpensive pitch and melamine. The skeletons of TDSC are optimized with shortened graphite‐like microcrystals, enlarged interlayer spacing, and abundant topological defects (e.g., pentagons, heptagons, and octagons), which endow TDSC with fast pseudocapacitive K‐ion intercalation behavior. Meanwhile, micrometer‐sized structure can reduce the electrolyte degradation over particle surface and avoid unnecessary voids, ensuring a high initial Coulombic efficiency as well as high energy density. These synergistic structural advantages contribute to excellent rate capability (116 mA h g −1 at 20 C), impressive areal capacity (1.83 mA h cm −2 with a mass loading of 8.32 mg cm −2 ), long‐term cycling stability (capacity retention of 91.8% after 1200 h cycling), and low working temperature (−10 °C) of TDSC anodes, demonstrating great potential for the practical application of PIBs.