Highly Reversible Cuprous Mediated Cathode Chemistry for Magnesium Batteries

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• Magnesium batteries face challenges with sluggish kinetics and poor reversibility, limiting their volumetric capacity.
• Existing cathode chemistries hinder efficient energy storage in magnesium-based systems.

Purpose of the Study:

• To develop a novel cathode chemistry for magnesium batteries utilizing cuprous ions (Cu+) as charge carriers.
• To decouple energy storage from traditional cathode electrochemistry for improved performance.

Main Methods:

• Investigated the generation of Cu+ via a rapid equilibrium between a copper selenide electrode and a magnesium electrolyte.
• Explored the reversible chemical magnesiation/de-magnesiation driven by this solid/liquid equilibrium.
• Analyzed the discharge process where Cu+ reduction drives magnesiation and the recharge process involving Cu to Cu+ redox.

Main Results:

• Achieved a high reversible areal capacity of 12.5 mAh/cm² with a high electrode mass loading of 49.1 mg/cm².
• Demonstrated 80% capacity retention over 200 cycles following a conditioning process.
• Successfully decoupled energy storage from cathode electrochemistry using Cu+ mediation.

Conclusions:

• The novel Cu+ mediated cathode chemistry offers a promising solution for high-performance magnesium batteries.
• This approach addresses key challenges in magnesium battery development, paving the way for advanced energy storage solutions.