Li 2 MnO 3 : A Catalyst for A Liquid Cl 2 Electrode in Low-Temperature Aqueous Batteries.

Li 2 MnO 3 has been contemplated as a high-capacity cathode candidate for Li-ion batteries; however, it evolves oxygen during battery charging under ambient conditions, which hinders a reversible reaction. However, it is unclear if this irreversible process still holds under sub-ambient conditions. Here, we evaluated the low-temperature electrochemical properties of Li 2 MnO 3 in an aqueous LiCl electrolyte and observed a reversible discharge capacity of 302 mAh/g at a potential of 1.0 V versus Ag/AgCl at -78 °C with good rate capability and stable cycling performance, in sharp contrast to the findings in a typical Li 2 MnO 3 cell cycled at room temperature. However, our results reveal that the capacity does not originate from the reversible oxygen oxidation in Li 2 MnO 3 but the reversible Cl 2 (l)/Cl - (aq.) redox from the electrolyte. Our results demonstrated the good catalytic properties of Li 2 MnO 3 to promote the Cl 2 /Cl - redox at low temperatures. This article is protected by copyright. All rights reserved.