Highly Reversible Aqueous Anode-Free Cadmium-Bromine Batteries

Area of Science:

• Electrochemistry
• Materials Science
• Energy Storage

Background:

• Aqueous anode-free zinc batteries face challenges like dendritic growth and low utilization (<20%).
• Cadmium (Cd), a zinc analogue, offers potential for improved anode performance.
• Developing stable, high-energy aqueous batteries is crucial for next-generation energy storage.

Purpose of the Study:

• To systematically compare zinc and cadmium anodes in aqueous media.
• To demonstrate the first aqueous anode-free cadmium-bromine (Cd-Br) battery.
• To enhance the performance of anode-free Cd-Br batteries through electrolyte modification.

Main Methods:

• Comparative electrochemical analysis of Zn and Cd anodes in aqueous electrolytes.
• Fabrication and testing of anode-free Cd-Br and Zn-Br coin and pouch cells.
• Electrolyte engineering by introducing LiCl to the CdSO4 electrolyte to modify the Cd2+ solvation shell.

Main Results:

• Cadmium anodes exhibited dendrite-free deposition, suppressed side reactions, and stable cycling up to 75% utilization.
• Anode-free Cd-Br coin cells achieved 87.6% capacity retention after 2000 cycles.
• Scaled-up anode-free Cd-Br pouch cells demonstrated 83.8% retention after 1250 cycles with 157 Wh kg−1 energy density.

Conclusions:

• Cadmium is a superior anode material compared to zinc for aqueous anode-free batteries.
• The developed aqueous anode-free Cd-Br battery offers high energy density and exceptional cycling stability.
• This work establishes anode-free Cd-Br chemistry as a promising platform for high-performance aqueous batteries.