Polymer electrolytes are promising candidates as separators in lithium metal batteries. Here, authors reveal the existence of local lithium-based crystallites inside the polymer electrolyte in a lithium symmetric cell. A combination of unique operando wide-angle X-ray scattering with a nano-sized beam and complementary spectroscopic techniques identifies these crystallites as lithium carbonate, lithium hydroxide, and even metallic lithium. It is shown that these crystallites lower the ionic conductivity and the transference number.
- Fabian A. C. Apfelbeck
- Gilles E. Wittmann
- Peter Müller-Buschbaum
