SUM FREQUENCY GENERATION IN TANDEM WITH CYCLIC-VOLTAMMETRY: UNVEILING THE SOLID ELECTROLYTE INTERFACE ON SI ANODE AND AU CATHODES

摘要

Unlike ultra-sophisticated smartphones that are powered up to 12 hours long from a single light weight Li-ion battery the same performance has not yet been achieved for an electrical vehicle. High capacity electrodes like Si anodes exhibit high discharge rates, yet their cycling ability is poor mainly due to fracturing during the lithiation process. Li - air batteries demonstrate ingenuity in their cathode design but again fail after a few charge / discharge cycles. Both systems fail due to the same criteria - poor stability of the solid electrolyte interface (SEI), the chemical make-up and formation of which is still largely unknown. In the Li-ion system the Solubility (or rather insolubility) of the SEI on Si anodes is vital to preventing electrolyte consumption at the Si anode surface. In Li-oxygen (air) systems maintaining a critical thickness of the Li2O2 SEI is crucial in order to prevent the death of the cell.