# Redox Oligomer Assembling Hierarchical Reinforced Framework Cathodes for Ultra‐Stable High‐Performance Zinc‐Ion Batteries

## TL;DR

A new cathode design for zinc-ion batteries improves performance and stability by using a redox oligomer in a reinforced framework.

## Contribution

A novel hierarchical reinforced framework cathode is developed for ultra-stable zinc-ion batteries with high capacity and long cycling.

## Key findings

- The cathode achieved a specific capacity of 339.5 mAh g−1 at 0.1 A g−1.
- It retained 87.5% capacity after 65,000 cycles at 10 A g−1.
- The Zn2+ diffusion coefficient was calculated to be between 10−8 and 10−7 cm2 s−1.

## Abstract

Organic cathodes with maximal redox active‐sites and structural tunability are in great demand for aqueous zinc‐ion batteries (ZIBs). Currently, they are facing challenges of limited capacity, poor cycling stability, and sluggish ion transport in practical applications. In this work, we have developed a universal and efficient strategy to assemble a redox oligomer into a conductive substrate imitating a reinforced concrete framework as freestanding cathodes for high‐performance ultrastable ZIBs. The signature molecule was specifically designed by sandwiching phenoxoline with two benzoquinone units to explore the most redox‐active sites. 2D MXene nanosheets convalently bonded with single‐walled carbon nanotubes to construct hierachical reinforced framework with superior porosity and structural rigidity. Benefiting from superior structural robustness and electrochemical dynamics, the cathodes deliver the highest specific capacity of 339.5 mAh g−1 at 0.1 A g−1, together with exceptional capacity retention of 87.5% over 65 000 cycles at 10 A g−1. The calculated Zn2+ diffusion coefficient (10−8‐10−7 cm2 s−1) indicates rapid charge transfer kinetics. The assembled pouch cell demonstrates stable power output under various bending angles for a flexible energy supply. This work provides not only a novel nanostructure engineering strategy for fabricating high‐performance hierarchical electrodes but also insights into the design of redox‐rich molecules for next‐generation energy storage.

Redox phenoxoline‐benzoquinone oligomer has been designed as reinforced concrete framework like freestanding cathodes for high‐performance ZIBs. An optimal specific capacity of 339.5 mAh g−
1 was contributed with exceptional retention of 87.5% after 65 000 cycles at 10 A g−
1. Flexible energy storage is also demostrated. The excellent rate performance and cycling stability underscore the electrode design for advanced energy storage.