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A High Energy Density Aqueous Battery Achieved by Dual Dissolution/Deposition Reactions Separated in Acid‐Alkaline Electrolyte
Author(s) -
Liu Chang,
Chi Xiaowei,
Han Qi,
Liu Yu
Publication year - 2020
Publication title -
advanced energy materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 10.08
H-Index - 220
eISSN - 1614-6840
pISSN - 1614-6832
DOI - 10.1002/aenm.201903589
Subject(s) - electrolyte , faraday efficiency , materials science , electrochemistry , anode , cathode , battery (electricity) , aqueous solution , flow battery , dissolution , chemical engineering , electrode , redox , electrochemical window , capacity loss , inorganic chemistry , chemistry , ionic conductivity , metallurgy , organic chemistry , thermodynamics , power (physics) , physics , engineering
Aqueous batteries are facing big challenges in the context of low working voltages and energy density, which are dictated by the narrow electrochemical window of aqueous electrolytes and low specific capacities of traditional intercalation‐type electrodes, even though they usually represent high safety, low cost, and simple maintenance. For the first time, this work demonstrates a record high‐energy‐density (1503 Wh kg −1 calculated from the cathode active material) aqueous battery system that derives from a novel electrolyte design to expand the electrochemical window of electrolyte to 3 V and two high‐specific‐capacity electrode reactions. An acid‐alkaline dual electrolyte separated by an ion‐selective membrane enables two dissolution/deposition electrode redox reactions of MnO 2 /Mn 2+ and Zn/Zn(OH) 4 2− with theoretical specific capacities of 616 and 820 mAh g −1 , respectively. The newly proposed Zn–Mn 2+ aqueous battery shows a high Coulombic efficiency of 98.4% and cycling stability of 97.5% of discharge capacity retention for 1500 cycles. Furthermore, in the flow battery based on Zn–Mn 2+ pairs, more excellent stability of 99.5% of discharge capacity retention for 6000 cycles is achieved due to greatly improved reversibility of the Zn anode. This work provides a new path for the development of novel aqueous batteries with high voltage and energy density.