Recent years have seen a growing development of aqueous batteries featuring high safety, low cost, and excellent performance. However, they are facing great challenges in large scale applications due to their low working voltage and energy density, which are caused by the narrow electrochemical window of aqueous electrolyte (1.23 V) and low specific capacities of traditional intercalation-type electrodes.

Recently, a research team led by Professor Liu Yu and Chi Xiaowei from the Shanghai Institute of Ceramics innovatively proposed a high-energy-density (1503 Wh kg^-1 calculated from the cathode active material) aqueous battery system achieved by dual dissolution/deposition reactions separated in acid-alkaline electrolyte. An acid-alkaline dual electrolyte separated by an ion-selective membrane successfully expands the electrochemical window of electrolyte to 3 V, and also enables two dissolution/deposition electrode redox reactions of MnO₂/Mn²⁺ and Zn/Zn(OH)₄^2- with respective theoretical specific capacities of 616 mAh g^-1 and 820 mAh g^-1.

The newly proposed Zn-Mn²⁺ aqueous battery shows high coulombic efficiency of 98.4 percent and cycling stability of 97.5 percent of discharge capacity retention for 1500 cycles. Furthermore, the excellent stability of 99.5 percent of discharge capacity retention for 6000 cycles is achieved in the flow battery based on the Zn-Mn²⁺ pairs.

Related research results were published in Advanced Energy Materials (2020, DOI: 10.1002/aenm.201903589) and selected to be featured on the inside cover of the journal. This work provides a new approach for the development of novel aqueous batteries with high voltage and energy density.

Fig. 1 Schematic illustration and mechanism of a Zn-Mn²⁺ battery using an acid-alkaline dual electrolyte

The first author of this work is Liu Chang, a PhD student from the Shanghai Institute of Ceramics. His supervisor is Professor Liu Yu.

For more information, please contact:

Prof. Liu Yu

Email: yuliu@mail.sic.ac.cn

Shanghai Institute of Ceramics, Chinese Academy of Sciences

Source: Shanghai Institute of Ceramics,

Chinese Academy of Sciences