Ultrastable Surface‐Dominated Pseudocapacitive Potassium Storage Enabled by Edge‐Enriched N‐Doped Porous Carbon Nanosheets

Abstract

The development of ultrastable carbon materials for potassium storage poses key limitations caused by the huge volume variation and sluggish kinetics. Nitrogen‐enriched porous carbons have recently emerged as promising candidates for this application, however, rational control over nitrogen doping is still challenging to further improve the long‐term capacity fading. Here we propose a pyridine‐coordinated polymer pyrolysis‐etching strategy for deliberate manipulation of edge‐nitrogen doping and specific spatial distribution in amorphous high‐surface‐area carbons, which shows an edge‐nitrogen up to 9.34 at%, richer N distribution inside materials and high surface area of 616 m2 g‐1 under a cost‐effective low‐temperature carbonization. The optimized carbon delivers unprecedented K‐storage stability over 6000 cycles with negligible capacity decay (252 mAh g‐1 after 4 months at 1 A g‐1), rarely reported for potassium storage. In‐depth analyses reveal high edge nitrogen, spatial distribution and high surface area together bring an impressive surface‐dominated capacitive storage mechanism providing ultrastable performance.