Robust Solid/Electrolyte Interphase (SEI) Formation on Si Anodes Using Glyme-Based Electrolytes
Guang Yang, Sarah Frisco, Runming Tao, N Philip, Tyler H. Bennett, Caleb Stetson, Ji‐Guang Zhang, Sang‐Don Han, Glenn Teeter, Steven P. Harvey, Yunya Zhang, Gabriel M. Veith, Jagjit Nanda
Abstract
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.