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Air self-charging aqueous metal-ion batteries typically suffer from capacity loss after self-charging cycles due to the formation of alkaline salts on the cathode in near-neutral electrolytes. Recently, the team of Niu Zhiqiang of Nankai University developed an air self-charging Pb/PTO battery based on proton chemistry in an acidic electrolyte. The fast kinetics of H+ insertion/extraction/removal endow the battery with enhanced electrochemical performance. Due to the high standard electrode potential of oxygen in the acidic electrolyte, the positive electrode after discharge is spontaneously oxidized by oxygen in the air, and H+ is extracted at the same time, thereby realizing self-charging without an external power supply. It is worth noting that the air self-charging mechanism involving H+-based redox can effectively avoid the generation of alkaline salts on the self-charging electrodes, thereby ensuring long-term self-charging/galvanostatic discharge cycles of Pb/PTO batteries. This work provides a promising strategy for designing long-cycle air self-charging systems. The results were published in the internationally renowned journal Angew. Chem. Int. Ed. titled “Proton Chemistry Induced Long-Cycle Air Self-Charging Aqueous Batteries”.

Figure 1. Schematic illustration of the self-charging of acidic and near-neutral electrolytes in Pb/PTO batteries.

▲ Compared with metal ions, H+ ions have a smaller ionic radius, which will significantly improve the reaction kinetics of the battery, thereby contributing to the excellent air charging capability. In addition, in H+-based batteries, the formation of acidic electrolytes and alkaline salts will be effectively suppressed. The authors developed an air self-charging Pb/PTO air self-charging battery. Charged Pb/PTO cells exhibit H+ intercalation/extraction and fast kinetics. During self-charging in acidic media, oxygen is reduced to form water molecules in the presence of H+ ions (Figure 1). The formation of alkaline salt PTO electrode is effectively avoided, and the long-term chemical self-charge-discharge cycle of Pb/PTO battery is guaranteed. Furthermore, the standard electrode potential of the oxo-acid medium is higher than that of the neutral medium, resulting in a larger potential difference between the discharge cathode and oxygen. Therefore, the Pb/PTO battery achieves enhanced air rechargeability.

Literature information

Fang Yue, Zhiwei Tie, Yan Zhang, Songshan Bi, Yijing Wang, Zhiqiang Niu*, Proton Chemistry Induced Long-Cycle Air Self-Charging Aqueous Batteries, Angew. Chem. Int. Ed. anie.202208513

Reviewing Editor: Li Qian

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