Polyacrylonitrile Alcoholysis and Freeze‐Expanded Assistive Synthesis of Porous Carbon for High Rate Supercapacitors and Zinc‐Ion Hybrid Capacitors

Although energy storage devices have made great progress in recent years, their electrode materials still face some problems, such as the lack of high‐power and high rate performance in lithium battery materials, and poor energy density in capacitor materials. Here, we utilizes polyacrylonitrile (PAN) alcoholysis derivatives as a carbon source to prepare hierarchical porous carbon with a high specific surface area, and employ freeze‐expansion method to increase pore size and improve its high magnification performance. The final hierarchical porous carbon material has high specific surface area (2941 m 2 g −1 ) and rich N/O doping. The porou carbon applied in supercapacitors exhibits high‐rate performance (200.5 F g −1 at 100 A g −1 ), high energy density (12.61 Wh kg −1 at 150 W kg −1 ) and excellent stability in symmetric supercapacitors. Furthermore, it owns high energy density (120.9 Wh kg −1 at 160 W kg‐1) in a zinc‐ion hybrid capacitors. The excellent electrochemical performance is further demonstrated by in situ electrochemical quartz crystal microbalance and ex situ characterizations. The PAN alcoholysis and freeze‐expanded methes provides a novel strategies for the preparing of hierarchical porous carbon based on PAN, and a new insights to expand the pore size of porous carbon.