Abstract:

In this study, high ionic conductivity monomers and initiators were introduced into the silicon anode electrode electrolyte by taking advantage of the spontaneous polymerization of polymer monomers and initiators under heating. The in situ solidified silicon anode electrode cell was prepared by thermal polymerization after liquid injection. The cycle and rate properties of the cell were tested using charging and discharging equipment. The morphology and electrochemical properties of the silicon anode electrode were characterized using scanning electron microscopy, X-ray diffraction spectrometer, and electrochemical workstation and mercury porosimeter. The results show that the number of cycles of the solidified cell at room temperature of 0.5 C is 349 cycles, which is 51.74% higher than that of the liquid cell at 230 cycles. The swelling rate of the silicon anode electrode after solidification is 4.6% lower than that of the liquid cell, and the porosity of the electrode is 3.8% lower than that of the liquid cell. The EIS and DCIR growths after cycling are reduced, and the performance of the cell is significantly better than that of the liquid core. The electrode sheet characterization results show that solidification can improve the interface of the silicon anode electrode plate, form a layer of polymer electrolyte on the surface of the silicon anode electrode and in the hole of the electrode plate, prevent the silicon anode electrode plate from swelling, powdering and falling off when lithium is embedded, and stabilize the ion and electronic conductive network of the electrode plate. This research promotes the application of silicon anodes and provide an experimental basis for the research and development of battery technology involving high energy density.

Key words: in-situ solidification, silicon oxide anode, electrode interface, swelling