MIT researchers have discovered that dendrites in solid-state batteries grow due to chemical reactions rather than purely mechanical stress. Using birefringence microscopy to directly measure stress around growing dendrites, they found cracks form at stress levels as low as 25% of what mechanical stress alone would predict. High electrical currents cause chemical reactions that embrittle the electrolyte — reducing its toughness from something like a tooth to something as brittle as a lollipop. The findings, published in Nature, explain why building stronger electrolytes hasn't solved the dendrite problem and point toward the need for more chemically stable electrolyte materials to unlock the potential of high-energy-density solid-state batteries.
Sort: