ELECTRICAL CONDUCTIVITY OF COEXISTING SYSTEM CONTAINING INORGANIC POWDER AND AMBIENT-TEMPERATURE MOLTEN SALTS

摘要

The electrical conductivity was measured for the coexisting system containing the α-Al_2O_3 powder and RTMS, i. e. trimethyl-n-propyl ammonium bis(trifluoromethylsulfonyl)imide(TMPA-TFSI) and binary RTMS which containing TMPATFSI added HTFSI as a proton source; H/TMPA-TFSI. For the system containing the inorganic powder and TMPATFSI, the electrical conductivity increased exponentially as the liquid content increased, and depended on the specific surface area of the powder. The conductivity showed the temperature dependence following the VTF (Vogel-Tammann-Fulcher) equation. Whereas the melting point of bulk sample was observed at 25.8℃, it decreased with an increase of the specific surface area of the solid phase. The molar enthalpy of fusion also decreased. It is suggested that the phase transition behavior is influenced by the coexistence of the porous solid phase. Since HTFSI does not dissociate in the TMPATFSI and does not contribute to the conduction in the bulk system, the electrical conductivity decreased with the increase of the HTFSI content in the bulk system. However, in the coexisting system, the conductivity increased, and the activation energy decreased with the HTFSI content up to 0.4 of [H~+]/cation. It is expected that the conductivity is enhanced near the solid surface by the contribution of proton of HTFSI.