US team toughens ceramic electrolytes for safer solid-state batteries

Stanford University researchers have developed a method to significantly improve the mechanical durability of ceramic electrolytes used in solid-state batteries, addressing their inherent brittleness that leads to cracking and battery failure. By applying an ultra-thin, 3-nanometer silver coating onto the lithium lanthanum zirconium oxide (LLZO) electrolyte and annealing it at 300°C, silver ions diffuse into the electrolyte, replacing smaller lithium ions and creating a positively charged structural barrier. This nanoscale silver doping enhances fracture resistance by nearly five times and prevents lithium from wedging into microscopic surface cracks, which typically expand during fast charging and cause destructive fissures. The study highlights that this silver ion diffusion fundamentally changes how cracks initiate and propagate, making the electrolyte more stable under extreme electrochemical and mechanical conditions. While other ions like copper showed some effectiveness, silver remains the most efficient for this purpose. The team is now scaling up from small samples to full battery cells to test the coating’s durability over thousands of charge cycles,