Multiple Redox‐Active Cyano‐Substituted Organic Compound Integrated with MXene Nanosheets for High‐Performance Flexible Aqueous Zn‐Ion Battery

Abstract

An eco‐friendly organic compound, with rich redox sites, considered a promising cathode material for aqueous zinc‐ion batteries (AZIBs). Despite its potential, limited specific capacity and cycle instability impede its practical application. Herein, an organic compound, hexaazatriphenylene hexacarbonitrile (6CN‐HAT), is designed with a π–π conjugated aromatic structure, and integrated with MXene nanosheets to construct a flexible self‐supporting electrode (6CN‐HAT@MXene). Ex‐situ characterizations and theoretical calculations verify that the charge storage mechanism predominantly involves coordination and non‐coordination reactions between reactive C═N and ─CN sites with cations. The introduction of MXene nanosheets not only bolster the stability and electronic conductivity of the 6CN‐HAT@MXene but also expose additional active sites for cation coordination. As a cathode material in AZIBs, 6CN‐HAT@MXene exhibits an outstanding discharge specific capacity of 413 mAh g−1 at 0.05 A g−1. Remarkably, even after 5000 cycles at 5 A g−1, the discharge capacity retained 91%. Furthermore, based on the 6CN‐HAT@MXene electrode, a flexible micro‐zinc‐ion batteries with high area capacity of 257.4 mF cm−2 is prepared using laser cutting technology, highlighting its potential for future applications in portable and wearable electronic devices.