Professor Dennis Y.C. Leung of the Department of Mechanical Engineering had worked on the research for the topic “Reversibility of a High‐Voltage, Cl–‐Regulated, Aqueous Mg Metal Battery Enabled by a Water‐in‐Salt Electrolyte”. The research has beenis recently published by ACS Energy Letters on July 21, 2022.
Details of the publication:
Reversibility of a High‐Voltage, Cl–‐Regulated, Aqueous Mg Metal Battery Enabled by a Water‐in‐Salt Electrolyte
Kee Wah Leong, Wending Pan, Yifei Wang, Shijing Luo, Xiaolong Zhao, and Dennis Y. C. Leung, Article in ACS Energy Letters, https://pubs.acs.org/doi/10.1021/acsenergylett.2c01255
Rechargeable Mg batteries are a promising post-Li-ion battery technology, but their development has been critically hampered by the passivating nature of Mg, particularly in aqueous solutions. Due to a quick dismissal of its reversibility, the use of Mg anodes in aqueous electrolytes has been overlooked, and most researchers focus on nonaqueous systems instead. In this work, reversible, aqueous Mg battery chemistry has been realised for the first time, via the conversion of its impermeable passivation film to a conductive metallic oxide complex, facilitated by Cl– regulation and the suppression of the hydrogen evolution reaction using a MgCl2 water-in-salt (WIS) electrolyte. When coupled with copper hexacyanoferrate as the cathode, the full battery exhibits an impressive voltage plateau of 2.4–2.0 V and a stability of over 700 cycles with a Coulombic efficiency of up to 99% at 0.5 A g–1. Mg dissolution and deposition have proven reversible in the aqueous MgCl2 WIS electrolyte.