Covalent Organic Framework with Highly Accessible Carbonyls and π‐Cation Effect for Advanced Potassium‐Ion Batteries

作者：Luo XiaoXi; Li WenHao; Liang HaoJie; Zhang HongXia; Du KaiDi; Wang XiaoTong; Liu XinFang; Zhang JingPing; Wu XingLong

来源：Angewandte Chemie, 2022, 134(10).

DOI：10.1002/ANGE.202117661

• Covalent Organic Framework
• Energy Storage
• Organic Anode
• Potassium-Ion Battery

Covalent organic frameworks (COF) possess a robust and porous crystalline structure, making them an appealing candidate for energy storage. Herein, we report an exfoliated polyimide COF composite (P‐COF@SWCNT) prepared by an in situ condensation of anhydride and amine on the single‐walled carbon nanotubes as advanced anode for potassium‐ion batteries (PIBs). Numerous active sites exposed on the exfoliated frameworks and the various open pathways promote the highly efficient ion diffusion in the P‐COF@SWCNT while preventing irreversible dissolution in the electrolyte. During the charging/discharging process, K+ is engaged in the carbonyls of imide group and naphthalene rings through the enolization and π‐K+ effect, which is demonstrated by the DFT calculation and XPS, ex‐situ FTIR, Raman. As a result, the prepared P‐COF@SWCNT anode enables an incredibly high reversible specific capacity of 438?mA?h?g?1 at 0.05?A?g?1 and extended stability. The structural advantage of...