Temperature-Dependent Solubility of Solid Electrolyte\nInterphase on Silicon Electrodes

The\nlithium-ion batteries powering mass market electric vehicles\nmust be capable of operating in a wide temperature range. Temperature\nvariation has the potential to greatly affect the stability of the\nsolid electrolyte interphase (SEI) responsible for mitigating capacity\nfade due to electrolyte decomposition in the lithium-ion battery.\nIn this work, we investigate the solubility of the SEI on the silicon\n(Si) electrode, an alternative anode material to the conventional\ngraphite electrode, at temperatures ranging from −10 to 50\n°C. Through use of an electrochemical protocol with a high cathodic\ncutoff voltage, we measure the evolution of the SEI independently\nof competing Si mechanical stress. We correlate the electrochemical\ndata with three-dimensional resistivity versus depth profiling as\nwell as atomic force microscopy to show that SEI dissolution occurs\nat significantly faster rates at higher temperatures.