Promoting Reversible Dissolution/Deposition of MnO2 for High‐Energy‐Density Zinc Batteries via Enhancing Cut‐Off Voltage

• Published in: ChemSusChem 2022-09, Vol.15 (18), p.e202201118-n/a
• Main Authors: Ruan, Pengchao, Xu, Xilian, Zheng, Dong, Chen, Xianhong, Yin, Xinyu, Liang, Shuquan, Wu, Xianwen, Shi, Wenhui, Cao, Xiehong, Zhou, Jiang
• Format: Article
• Language: English
• Subjects: aqueous zinc batteries; cut-off-voltage; Deposition; Dissolution; Electric potential; electrochemistry; Energy storage; high energy density; Intercalation; Manganese dioxide; Reaction mechanisms; Voltage; Zinc
• ISSN: 1864-5631; 1864-564X
• DOI: 10.1002/cssc.202201118

Zn//MnO2 batteries based on the MnO2/Mn2+ conversion reaction mechanism featuring high energy density, safety, and affordable cost are promising in large‐scale energy storage application. Nonetheless, the continuous H+ intercalation at low potential reduces the average output voltage and the energy efficiency, impeding the development of the high‐performance zinc battery. In this work, a strategy was proposed of enhancing the cut‐off voltage from the perspective of electrochemical parameters, toward high energy efficiency and stable output voltage of the Zn//MnO2 battery. This strategy was beneficial to promoting MnO2 dissolution/deposition through the increase of acidity caused by the constant accumulation of MnO2 and inhibiting H+ (de)intercalation during cycling process, thereby improving the energy efficiency (83.5 %) along with the stable average output voltage (1.88 V) under the cut‐off voltage of 1.8 V. This work provides a new pathway to promote aqueous zinc batteries with high energy density and stable output voltage. Cutting edge: High‐energy‐density Zn//MnO2 batteries are usually plagued by H+ (de)intercalation, resulting in low energy efficiency. Here, low potential H+ (de)intercalation is suppressed by enhancing cut‐off voltage and promoting the MnO2 dissolution/deposition reaction by the accumulated H+, thus improving the energy efficiency while ensuring high coulombic efficiency. This provides a new research idea for high‐energy‐density zinc batteries.