This work focuses on fundamental problems of gel electrolytes studied concerning their application in rechargeable lithium batteries. Gel electrolyte films were prepared by photopolymerization of appropriate monomers (oligo(ethylene glycol)n dimethacrylates, their copolymerization with polar comonomers, i. e. arcylonitrile, cyanomethyl methacrylate, cyclocarbonatopropyl methacrylate as well as the alternating copolymerization of oligo(ethylene glycol)4divinylether with maleic anhydride) in the presence of a liquid component, (various oligo(ethylene glycol)n dimethylether, PC) and a salt (LiCF3SO3). Relationships between the structure of the gel electrolytes and their properties were established on the basis of structural and thermal investigations (DSC, DMA, AFM and positron annihilation lifetime spectroscopy), the characterization of the ionic assoziation (Raman spectroscopy), the measurement of the ionic conductivity (impedance spectrometry, DK) and self-diffusivity (7Li-, 19F- and 1H- pulsed field gradient - NMR) and the determination of the cationic transference number (t+). The electrochemical properties of the electrolytes were also characterized by cyclic voltammetry and cyclisation of lithium ion batteries. |