Designing Solid Electrolyte Interface for Stabilized Silicon Anode for Lithium-Ion Battery

Abstract

The exploration for the next generation of anode materials in the lithium-ion batteries is a vital subject in energy storage field. Silicon (Si) stands out among all the candidate materials due to its high theoretical specific capacity (4200 mAh/g for Li4.4Si), high safety and low cost. However, one of the biggest issues causing rapid capacity fade of Si anode is the continuous breakage and reformation of SEI due to unstable electrode/electrolyte interphase. One effective way to address it is to use electrolyte additives as represented by vinylene carbonate (VC) and fluoroethylene carbonate (FEC). It is believed that the decomposition of FEC generates electrochemical stable LiF and elastomeric polymerizable vinylene carbonate radical. These decomposition products form a passive layer on Si surface, leading to improved electrochemical performance. However, it is hard to control the composition and structure of the SEI.We take a different approach attempting to solve the above issue. Organic functional groups are introduced on the surface of Si nanoparticles (SiNPs) via Pt-catalyzed hydrosilylation reaction. The surface group helps form more robust SEI thus boosts the electrochemical performance of silicon anode evidenced in both half- and full-cells. This method provides an efficient approach confronting the issues associated with SEI. Figure 1