Study on the advanced electrolytes for enhancing the performance of electrochemical energy devices

Abstract

Development of new materials is key issue in electrochemical energy devices, both of which are vital to meet the challenge of global warming and the limited nature of fossil fuels. As you know, the performance of electrochemical energy devices depends intimately on the properties of their materials. Common features are that the energy-providing processes take place at the phase boundary of the electrode/electrolyte interface and that electron and ion transport are separated. Note that batteries and photoelectrochemical cells, especially, dye-sensitized solar cells all consist of two electrodes in contact with an electrolyte. We focus on the electrolyte systems in lithium rechargeable batteries and dye-sensitized solar cells. In Chapter Ⅱ, it is devoted to modify the surface of PE separator with functional materials by electron beam irradiation technique, and then prepared electrolyte containing modified separator. Anion receptor is known to be a new promising material, because it can enhance cationic conductivity and electrochemical stability of electrolyte. And also siloxane is famous for enhancing the safety of battery. If the advanced electrolyte with higher electrochemical stability is developed, the energy density of the battery system can be enhanced far superior to state-of-art battery system. In Chapter Ⅲ, poly(ethylene glycol) borate acrylate (PEGBA) was synthesized as a new crosslinking agent for solid polymer electrolyte (SPE) based on non-woven matrix. It has not only three crosslinkable acrylate groups for higher crosslinking density, but also Lewis acid center acting as an anion receptor. The ionic conductivity of SPE containing 15 wt% PEGBA reached $5.5 \times10^{-4} S/cm$, because the content of non-volatile plasticizer, poly(ethylene glycol) dimethyl ether (PEGDME), could be increased to 85 wt% without leakage. In addition, its transference number and electrochemical stability were also enhanced to 0.37 and 5.2V, respectively, due to the prese...