Overview
- Researchers extracted individual dendrites from coin cells and measured their behavior using a nanomanipulator inside a scanning electron microscope and a miniature mechanical tester.
- Cryogenic electron microscopy revealed a single-crystal lithium core encased by a thin solid electrolyte interphase that stiffens the structures and suppresses plastic deformation.
- Tensile measurements showed fracture strengths above roughly 150 MPa, far higher than the approximately 0.6 MPa strength of bulk lithium metal.
- The rigid, brittle needles can puncture separators or even crack solid electrolytes, causing internal short circuits and leaving isolated dead lithium that reduces capacity.
- Operando imaging confirmed brittle behavior in both liquid and solid electrolyte systems, and the Science paper suggests mitigation by tailoring electrolyte or SEI microstructures and modifying Li-metal anodes.