Electroconvective Flow in Liquid Electrolytes Containing Oligomer Additives.

Area of Science:

• Electrochemistry
• Materials Science
• Fluid Dynamics

Background:

• Metal electrodeposition in batteries is prone to instabilities, particularly electroconvection at high charging rates.
• Electroconvection causes nonuniform ion flux and preferential metal deposition, complicating battery operation and reducing lifespan.

Purpose of the Study:

• To investigate the effect of oligomer additives on electroconvection in liquid electrolytes.
• To elucidate the mechanism by which oligomers influence hydrodynamic instability at cation-selective interfaces.

Main Methods:

• Experimental investigation using electrochemical measurements.
• Direct visualization experiments to observe electroconvection dynamics.
• Study of oligomer additives in liquid electrolytes at a cation-selective interface.

Main Results:

• Oligomer additives were found to delay and suppress electroconvection across all tested voltages.
• The presence of an oligomer ad-layer at the electrode interface was identified as the key factor.
• This ad-layer appears to generate an opposing body force, preserving its structure and suppressing instability.

Conclusions:

• Surface forces from adsorbed oligomers can effectively suppress electroconvection in battery electrolytes.
• This provides a novel approach to enhance battery stability and performance by controlling hydrodynamic instabilities.
• Oligomer additives offer a promising strategy for mitigating electrodeposition issues without relying on bulk electrolyte elasticity.