Preferential Pyrolysis Construction of Carbon Anodes with 8400 h Lifespan for High‐Energy‐Density K‐ion Batteries

Carbonaceous materials are promising anodes for practical potassium‐ion batteries, but fail to meet the requirements for durability and high capacities at low potentials. Herein, we constructed a durable carbon anode for high‐energy‐density K‐ion full cells by a preferential pyrolysis strategy. Utilizing S and N volatilization from a π–π stacked supermolecule, the preferential pyrolysis process introduces low‐potential active sites of sp2 hybridized carbon and carbon vacancies, endowing a low‐potential “vacancy‐adsorption/intercalation” mechanism. The as‐prepared carbon anode exhibits a high capacity of 384.2 mAh g−1 (90 % capacity locates below 1 V vs. K/K+), which contributes to a high energy density of 163 Wh kg−1 of K‐ion full battery. Moreover, abundant vacancies of carbon alleviate volume variation, boosting the cycling stability over 14 000 cycles (8400 h). Our work provides a new synthesis approach for durable carbon anodes of K‐ion full cells with high energy densities. A durable carbon anode has been constructed for high‐energy‐density K‐ion batteries by a preferential pyrolysis strategy, in which the low‐potential active sites of sp2 hybridized C and vacancies were generated utilizing S and N volatilization from a π–π stacked supermolecule.