Improving the Energy Density of Potassium‐Ion Batteries Through Defect Engineering

Abstract Potassium‐ion batteries (PIBs) have a significant cost advantage in resources, making their commercial application imminent. Presently, the cycling lifespan and energy density of PIBs lag behind those of lithium‐ion batteries, highlighting the crucial need for anode materials suitable for potassium storage. This paper used high‐pressure heat treatment and extraction methods to obtained toluene insoluble (TI) as a carbon matrix, followed by nickel and nitrogen co‐doping to synthesized anode materials (NiNTI). NiNTI is characterized by defect engineering such as thermal condensation polymerization and template doping, which destroys the flattening of the material, provides more active sites, forms more disordered carbon structures, generates a large number of defects and structural vacancies, and improves the electronic conductivity of NiNTI materials. In the NiNTI half‐cell configuration, operating at a current density of 0.1 A g −1 , the reversible specific capacity reaches 364 mAh g −1 , with an initial coulombic efficiency of 64.9%.