Silicon (Si) is the most naturally abundant element possessing 10-fold greater theoretical capacity compared to that of graphite-based anodes. The practicality of implementing Si anodes is, however, limited by the unstable solid/electrolyte interphase (SEI) and anode fracturing during continuous lithiation/delithiation. We demonstrate that glyme-based electrolytes (GlyEls) ensure a conformal SEI on Si and keep the Si “fracture-free”. Benchmarking against the optimal, commonly used carbonate electrolyte with the fluoroethylene carbonate additive, the Si anode cycled in a GlyEl exhibits a reduced early parasitic current (by 62.5%) and interfacial resistance (by 72.8%), while cell capacity retention is promoted by >7% over the course of 110 cycles. A mechanistic investigation by X-ray photoelectron spectroscopy and energy-dispersive X-ray spectroscopy indicates GlyEl enriches Si SEI with elastic polyether but diminishes its carbonate species. Glyme-based electrolytes proved to be viable in stabilizing the SEI on Si for future high energy density lithium-ion batteries.

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