Aqueous solution

Chemistry

Materials science

Electrochemistry

Composite number

Engineering

Composite material

Power (physics)

Microcrystalline

Physics

Electrode

Energy storage

Crystallography

Nanotechnology

Organic chemistry

Quantum mechanics

Electrolyte

Graphene

Cathode

Battery (electricity)

Carbon fibers

Inorganic chemistry

Chemical engineering

Physical chemistry

Advanced Functional Materials

Aqueous dual‐ion batteries (DIBs) are promising for large‐scale energy storage due to low cost and inherent safety. However, DIBs are limited by low capacity and poor cycling of cathode materials and the challenge of electrolyte decomposition. In this study, a new cathode material of nitrogen‐doped microcrystalline graphene‐like carbon is investigated in a water‐in‐salt electrolyte of 30 m ZnCl 2 , where this carbon cathode stores anions reversibly via both electrical double layer adsorption and ion insertion. The (de)insertion of anions in carbon lattice delivers a high‐potential plateau at 1.85 V versus Zn 2+ /Zn, contributing nearly 1/3 of the capacity of 134 mAh g −1 and half of the stored energy. This study shows that both the unique carbon structure and concentrated ZnCl 2 electrolyte play critical roles in allowing anion storage in carbon cathode for this aqueous DIB.

A High‐Potential Anion‐Insertion Carbon Cathode for Aqueous Zinc Dual‐Ion Battery