화학공학소재연구정보센터
Solid State Ionics, Vol.158, No.3-4, 375-380, 2003
Li-ion cell with poly(acrylonitrile-methyl methacrylate)-based gel polymer electrolyte
Poly(acrylonittile-methyl methacrylate) (AMMA) plasticized with 1 in LiBF4 dissolved in gamma-butyrolactone (GBL) liquid electrolyte was studied as a gel polymer electrolyte (GPE) of Li-ion cell. Typically, a GPE composed of 12 wt.% AMMA and 88 wt.% liquid electrolyte has an ionic conductivity of 3.9 mS/cm at 20 degreesC and 1.1 mS/cm at -30 degreesC. Results of cyclic voltammetry showed that such a GPE is electrochemically stable to withstand the normal operation of a Li-ion cell. With this GPE, Li/graphite and Li/cathode half-cells presented 89% and 80%, respectively, of Coulombic efficiency (CE), in the first cycle and approached to unity in the following cycles. For graphite/GPE/cathode Li-ion cell, its initial CE was 82%, being close to the lower one of either half-cell. Due partially to high ionic conductivity of the GPE, the Li-ion cell can be reversibly cycled in a wide temperature range. In particular, the Li-ion cell retained as high as 66% of discharge capacity even at - 30 degreesC, as compared to that obtained at 20 degreesC, when it was cycled at 0.5 mA/cm(2) (similar to 0.5 degreesC) between 2.5 and 4.2 V.