Porous Structure‐Electrochemical Performance Relationship of Carbonaceous Electrode‐Based Zinc Ion Capacitors

Abstract

The porous structure is critical for carbonaceous electrode‐based zinc‐ion capacitors (ZICs) to achieve excellent electrochemical performance, but the corresponding porous structure‐electrochemical performance relationship is yet to be fully understand. Herein, three types of N‐doped carbons with different porous structures are developed to investigate the relationship between the pore size distribution and the electrochemical performance of the devices. The optimized porous carbon (LVCR) exhibits large electrochemical surface area, plentiful oxygen functional groups, and hierarchical porous structure that facilitates electron transfer and ion diffusion. Consequently, the LVCR‐based ZIC exhibits a remarkable peak power density of 31.4 kW kg−1 and an impressive specific energy density of 126.6 Wh kg−1. Moreover, it demonstrates exceptional longevity, retaining the capacitance of 97.7% even after undergoing 50 000 cycles. Systematic characterization demonstrates that the macroporous and mesoporous structures determine the different stages of Zn2+ storage kinetics. The excellent Zn2+ storage and electrochemical performance of LVCR are attributed to the fast ion transport channels provided by the hierarchical porous structure and facilitated reversible chemisorption and desorption. This work not only deepens the understanding of charge storage mechanism, but also provides guidelines for rationally designing carbonaceous materials toward high‐performance ZICs in the view of porous structure‐electrochemical performance relationship.