Boosting Electrolytic MnO2–Zn Batteries by a Bromine Mediator

• Published in: Nano letters Vol. 21; no. 20; pp. 8863 - 8871
• Main Authors: Zheng, Xinhua, Wang, Yongchao, Xu, Yan, Ahmad, Touqeer, Yuan, Yuan, Sun, Jifei, Luo, Ruihao, Wang, Mingming, Chuai, Mingyan, Chen, Na, Jiang, Taoli, Liu, Shuang, Chen, Wei
• Format: Journal Article
• Language: English
• Published: American Chemical Society 27-10-2021
• Subjects: MnO2−Zn battery; Bromine; Redox mediator; Large-scale energy storage
• ISSN: 1530-6984; 1530-6992
• DOI: 10.1021/acs.nanolett.1c03319

An aqueous electrolytic MnO2–Zn battery with eye-catching Mn2+/MnO2 cathode chemistry has been attracting immense interest for next-generation energy storage devices due to its irreplaceable advantages. However, the limited MnO2 conductivity restricts its long service life at high areal capacities. Here, we report a high-performance electrolytic MnO2–Zn battery via a bromine redox mediator, to enhance its electrochemical performance. The MnO2/Br2–Zn battery displays a high discharge voltage of 1.98 V with a capacity of ∼5.8 mAh cm–2. It also shows an excellent rate performance of 20 C with a long-term stability of over 600 cycles. Furthermore, the scaled-up MnO2/Br2–Zn battery with a capacity of ∼950 mAh exhibits a stable 100 cycles with a practical cell energy density of ∼32.4 Wh kg–1 and an attractively low energy cost of below 15 US$ kWh–1. The design approach can be generalized to other electrodes and battery systems, thus opening up new possibilities for large-scale energy storage.