| 학회 | 한국고분자학회 |
| 학술대회 | 2005년 가을 (10/13 ~ 10/14, 제주 ICC) |
| 권호 | 30권 2호 |
| 발표분야 | 분자전자 부문위원회 |
| 제목 | Ionic conductivity studies of plasticized PEO-Lithium chlorate-FIC filler composite polymer electrolytes |
| 초록 | Polymer electrolytes have received much attention due to the wide range of their applications in battery systems, fuel cells, sensors and other electrochemical devices. Polyethylene oxide (PEO) is one of the most popular polymer hosts and is able to complex with several metal salts to form the PEO-based polymer electrolyte. However, it is known that most PEO-based polymer electrolytes showed poor room temperature conductivity in the order of 10-7-10-8 S/cm. At operational temperature in the range of 80-100°C, the conductivity reached 10-3-10-4 S/cm because of high crystallinity in SPE. Earlier, we studied the properties of the (PEO)LiClO4-Li1.3Al0.3Ti0.7(PO4)3 composite polymer electrolyte (CPE) system, in which PEO was used as the polymer matrix, LiClO4 as a salt and Li1.3Al0.3Ti0.7(PO4)3 as an extra FIC particle (1.5 μm). We found that the CPE films with overall EO/Li=8 (Li from LiClO4and Li1.3Al0.3Ti0.7(PO4)3 and 15 wt.% Li1.3Al0.3Ti0.7(PO4)3 had the optimum conductivity. To investigate the effect of plasticizers on improving the conductivity of polymer electrolytes, the present work extends the previous study by adding plasticizers such as ethylene carbonate (EC) or propylene carbonate (PC) to the CPE films. The solution-cast technique was used to synthesize the samples. The differential scanning calorimetry (DSC), scanning electron microscopy (SEM) and electrical impedance spectroscopy (EIS) measurement were used to characterize the effects of various temperature, two plasticizers on conductivity. Fig. 1. Temperature dependence of conductivity of (PEO/plasticizer-LiClO4)- Li1.3Al0.3Ti0.7(PO4)3 films with various plasticizer contents. The DSC results revealed the absence of Tm in any of the plasticized films, and the decrease of Tg with increasing PC or EC content, suggesting that the amorphous phase becomes dominant and the segmental motions of the PEO polymer chains become easier in (PEO/plasticizer-LiClO4)-Li1.3Al0.3Ti0.7(PO4)3 films. SEM morphology showed that the crystalline domains with large spherulites disappeared, and that the surface morphology of PEO tended to become relatively smooth and homogeneous after the addition of plasticizer, LiClO4 and Li1.3Al0.3Ti0.7(PO4)3 to PEO. EIS measurement indicated that the temperature dependence of conductivity of the (PEO/plasticizer-LiClO4)-Li1.3Al0.3Ti0.7(PO4)3 polymer electrolyte films followed the VTF equation and that the conductivity increased with increasing temperature (see Fig. 1). The maximum conductivities for the two plasticized films are 7.759×10-4 S/cm with EC as a plasticizer and 4.851×10-4 S/cm with PC as a plasticizer. Additionally, as the EC or PC plasticizer content increased in the polymer electrolyte films, both the pre-exponential factor (A) and the pseudo activation energy (Ea) increased with the increasing conductivity of all films. Especially, A and Ea reached a maximum of 5.379 Scm-1K1/2 and 7.636×10-2 eV, respectively, at 40 wt.% EC, and 6.774 Scm-1K1/2 and 8.817×10-2 eV, respectively, at 40 wt.% PC. The ionic transference number (tLi+ ), which was measured in the range of 0.296-0.376, increased with increasing plasticizer (EC or PC) content. |
| 저자 | 왕옌제, 김덕준 |
| 소속 | 성균관대 |
| 키워드 | PEO; polymer electrolytes; ionic conductivity |
