Silicon/Graphite Anode Performance Improvement: A Combination of Atomic Layer-Deposited ZnO Coatings with a Fluoroethylene Carbonate Additive

This study presents an investigation into the properties of silicon/graphite anodes used in Li-ion batteries, focusing on the impact of ZnO coatings and the addition of fluoroethylene carbonate (FEC) to the electrolyte. We systematically compare the effects of ultrathin ZnO coatings on the silicon/graphite anode, prepared by using atomic layer deposition (ALD), with and without the FEC additive in the electrolyte. Both ZnO coatings and the FEC additive significantly influence the rate capability and long-term cycling stability of the anodes. The combination of ALD-deposited ZnO coatings with the FEC additive in the electrolyte exhibited the best performance, enhancing both the rate capability and capacity retention over extended cycling. These findings are further corroborated by electrochemical impedance spectroscopy (EIS), which highlights improvements in the anode performance. Additionally, post-mortem analysis using X-ray photoelectron spectroscopy (XPS) indicated an increased amount of LiF in the solid electrolyte interphase (SEI) layer. This increase in LiF content may contribute to the enhanced stability and performance observed in ZnO-coated anodes when combined with the FEC additive in the electrolyte.