Researchers at University of Maryland’s A James Clark School of Engineering, have addressed a key barrier to mass electric transport. This achievement could clear the path to high density electric vehicle batteries, with fast-charging abilities. The key to this proposal involves having less electro-osmotic drag in battery cells. We unpack what this term means, and the potential benefits it brings.
The Effect of Electro-Osmotic Drag in Batteries
Osmotic drag generically refers to movement of a liquid or a solvent, across a porous or liquid material, as induced by an applied electrical potential. In flow batteries, this solvent is ‘dragged along’ by moving ions.
The Maryland team observed how this phenomenon also occurs in lithium-ion batteries, where it plays a decisive role. In a nut shell, osmotic drag restricts the speed with which thick, energy-dense electrodes can accept charges.
The researchers used this knowledge to achieve less electro-osmotic drag in prototype lithium-ion batteries. Their novel design achieved an 80% state of charge in 13 minutes, without compromising the battery’s energy storage density.
This milestone could be a great step forward for electric vehicles. The current generation can take 20 to 100 times longer that gasoline-powered vehicles to top up their energy. If we could reduce that time to within 15 minutes, then we should expect an upsurge in interest in electric transport.
More About This Discovery and Benefits
In the end, the solution was quite simple. The Maryland researchers designed an electrolyte with weak cation solvation, and strong anion solvation. This variation enabled their thick-electrode, energy-dense batteries to achieve 80% charge within 13 minutes.
“The recognition of electro-osmotic drag over-potential, provides a new conceptual foundation for electrolyte design,” enthuses post doctoral researcher Chang-Xon Zhao.
“We see broader implications for technologies such as flow batteries, electro-refining, and membrane-based separators too.” His team collaborated with a number of other professional bodies to reach their conclusion.
More Information
The Slight Matter of Battery Density
Systems Approach to Fast Charging Lithium
Preview Image: University of Maryland Laboratory
