| Novel lithium salts synthesized at Clemson by Dr. DesMarteau's research group have been tested as possible candidates for preparing solid polymer electrolytes (SPE) to be used in rechargeable lithium batteries. One such series consisted of seven new dilithium salts with structures similar to that of lithium bis[(trifluoromethyl)sulfonyl] imide, or LiTFSI, which is the most used standard salt in the field of lithium polymer batteries. It has one of the highest ionic conductivities known when incorporated into polyether-based SPEs, it's safe, but it has a corrosive effect upon the Al or Ni collectors of a battery. Another series consisted of polyanions, mainly oligoanions, with structures similar to that of LiTFSI, in polyether hosts. The work focused especially on preparation of SPEs from the dilithium salts in a high-Mw poly(ethylene oxide) (PEO) or cross-linked low-M w poly(ethylene glycol) (PEG) host, and on the structural, thermal and electrochemical characterization of these SPEs. Also, the effect of ceramic nano-fillers (fumed silica) upon conductivity was explored for several of the new salts.; The search for suitable salts to be incorporated in polymer electrolytes continued with new derivatives of lithium (perfluorovinylether)sulfonate coupled with either a partially fluorinated alcohol (monolithium series) or a partially fluorinated diol (dilithium series). Again, high-Mw PEO was used as the polymer host.; SPEs characterization was accomplished using thermal methods (DSC), 1H and 19F NMR, X-ray diffraction and various electrochemical techniques such as: electrochemical impedance spectroscopy (EIS) and galvanostatic polarization. |
