Faraday Institution explains why solid-state batteries fail

According to foreign media reports, scientists at the Faraday Institution have made important progress in understanding the causes of solid-state battery failure.

(Photo source: azom)

Researchers have provided an answer to a key piece of this scientific puzzle.

New "beyond lithium-ion" battery chemistry designs should gradually improve the range and safety of electric vehicle batteries while providing cost-effectiveness. Solid-state batteries are a potential technology in this regard, however, they are subject to several key technical challenges and fail during charge and discharge, which hinders their large-scale application.

In addition, solid-state batteries will short-circuit after repeated charging and discharging. A common cause of battery failure is the growth of lithium dendrites. Finding a solution may usher in a new era of solid-state battery-powered electric vehicles .

Scientists from the Department of Materials, Chemistry and Engineering Sciences at the University of Oxford, working in collaboration with Diamond Light Source and the Paul Scherrer Institute in Switzerland, have produced strong evidence to support one of two competing theories, namely that lithium metal dendrites grow through the ceramic electrolyte, causing the battery to short-circuit at high charge rates.

The team used X-ray computed tomography, an imaging method very similar to a medical CAT scanner, combined with spatially mapped X-ray diffraction to visualize and characterize the processes that form dendrites and cracks inside operating solid-state batteries.

Initially, a cone-shaped pit-like crack forms in the electrolyte close to the lithium-plated anode. The crack propagates along a path with a porosity greater than the average for the ceramic.

Then, metallic lithium is deposited along the crack, which then widens the crack from the back, causing the crack to continue to expand. The crack front has already expanded before lithium deposition, so there is no lithium at the crack tip. Only when lithium plating is formed along the entire crack will the battery cell eventually short-circuit.