Toward a Mechanically Rechargeable Solid Fuel Flow Battery Based on Earth-Abundant Materials.

Area of Science:

• Electrochemistry
• Materials Science
• Energy Storage

Background:

• Metal-air batteries offer high energy density but suffer from material limitations like metal passivation.
• Existing energy storage solutions face challenges in balancing power and energy capacities.
• Need for advanced battery architectures that enable efficient recharging and mitigate material degradation.

Purpose of the Study:

• To investigate a solid fuel flow battery (SFFB) architecture combining metal-air energy density with flow battery modularity.
• To address limitations of traditional metal-air batteries through a novel SFFB design.
• To demonstrate the technical feasibility of the SFFB concept for energy storage applications.

Main Methods:

• Developed an SFFB architecture with a spatially separated metallic solid electrochemical fuel (SEF) and redox mediator (RM).
• Utilized a dissolved redox mediator to shuttle charges between the SEF and the anodic current collector.
• Operated a proof-of-concept SFFB cell for approximately 25 days to assess performance and feasibility.

Main Results:

• Demonstrated that metallic SEFs can repeatedly chemically reduce organic RMs, indicating stable electrochemical fuel cycling.
• Successfully operated a proof-of-concept SFFB cell for an extended period of 25 days.
• The SFFB architecture successfully decoupled power and energy components, enabling mechanical recharging.

Conclusions:

• The SFFB architecture presents a promising alternative for energy storage, overcoming key limitations of metal-air batteries.
• The study confirms the technical feasibility of the SFFB concept and its potential for efficient energy storage.
• Identified scientific and engineering pathways for future improvements in SFFB design and performance.