Critical Advances of Aqueous Rechargeable Ammonium Ion Batteries

Aqueous rechargeable batteries have drawn wide attention owing to the advantages of low cost, high safety, and rapid kinetic process. In recent years, the use of NH 4 + ions and other nonmetallic ions as carrier batteries has come into researchers’ view. The storage of NH 4 + shows fast diffusion kinetics and the ability to achieve highly reversible redox processes by forming hydrogen bonds between NH 4 + and electrode materials. Designing and exploration of advanced materials for NH 4 + storage are of high significance in building high‐performance aqueous battery systems. This review summarizes the latest advances of critical materials, including Prussian blue analogs, transition metal oxides, and organic compounds for NH 4 + batteries. Comparison of properties among different materials is discussed in detail. Different NH 4 + storage behaviors according to several kinds of materials are demonstrated. Finally, the challenges and valuable perspectives for the further development of aqueous NH 4 + batteries are also provided.