Li₂ MnO₃ : A Catalyst for a Liquid Cl₂ Electrode in Low-Temperature Aqueous Batteries

Area of Science:

• Electrochemistry
• Materials Science
• Energy Storage

Background:

• Lithium manganese oxide (Li₂ MnO₃) is a promising high-capacity cathode material for lithium-ion batteries.
• Oxygen evolution during charging at ambient temperatures limits its reversibility.
• The behavior of Li₂ MnO₃ under subambient conditions remains largely unexplored.

Purpose of the Study:

• To investigate the low-temperature electrochemical properties of Li₂ MnO₃.
• To determine the source of observed capacity at subambient temperatures.
• To evaluate the potential of Li₂ MnO₃ in cold environments.

Main Methods:

• Electrochemical evaluation of Li₂ MnO₃ in an aqueous LiCl electrolyte at -78 °C.
• Analysis of charge-discharge performance, rate capability, and cycling stability.
• Investigation of the redox mechanisms involved.

Main Results:

• A reversible discharge capacity of 302 mAh g^-1 was achieved at 1.0 V vs. Ag/AgCl at -78 °C.
• The material exhibited good rate capability and stable cycling performance.
• The observed capacity was attributed to the reversible Cl₂ (l)/Cl^- (aq.) redox from the electrolyte, not oxygen evolution.

Conclusions:

• Li₂ MnO₃ demonstrates significant reversible capacity at -78 °C.
• The lithium manganese oxide acts as a catalyst for electrolyte redox reactions at low temperatures.
• This study highlights the potential of Li₂ MnO₃ for batteries operating in cold climates.