| 학회 | 한국고분자학회 |
| 학술대회 | 2004년 가을 (10/08 ~ 10/09, 경북대학교) |
| 권호 | 29권 2호, p.99 |
| 발표분야 | 기능성 고분자 |
| 제목 | Electrochemical Behavior of Poly (vinyl alcohol)-based Solid Polymer Electrolytes Containing Fast Cationic Transport Process |
| 초록 | A series of poly (vinyl alcohol) (PVA)-lithium trifluoromethane sulfonate (LiCF3SO3) films were prepared by means of the solution cast technique. The thickness of the films was between 200 and 350㎛ and they contained 20~80wt% of salts. Conductivities of the solid polymer electrolytes (SPEs) were obtained from impedance measurements. The conductivity increased with the increase of the salt content up to 80wt% and the highest ionic conductivity was 1.42ⅹ10-3S/cm at room temperature for SPEs with 80wt% of salt concentration. Using FTIR, AFM and XRD, we found that ‘fast cationic transport process’ consisted of network-like connected large ion aggregates was formed at about 50wt% of salt concentration and over than this salt conc., lithium ion could move by ion hopping decoupled from polymer segmental motion inside of the ‘fast cationic transport process’. Besides the high ionic conductivity, the electrochemical stability and the reversibility of electrochemical behavior at the interface between electrode and electrolyte are significant parameters for practical electrolytes. So, in this study, we investigated electrochemical behavior of PVA-based SPEs before and after formation of ‘fast cationic transport process’. The electrochemical window of SPE was measured by the linear sweep voltammetry experiment. Fig. 1 shows the current response of the working electrode. The result exhibits that the electrochemical stability window is at least 4.5V for SPEs with more than 50wt% of salts. It means that PVA-based SPEs containing ‘fast cationic transport process’ have sufficient electrochemical stability for use in the lithium ion polymer battery. Not only good electrochemical stability but also reversible lithium deposition/stripping process in SPEs with the ‘fast cationic transport process’ was observed by cyclic voltammetry (CV). Also, from CV data, we could know when the salt concentration increased, the rate constant of the electrochemical processes increased and the diffusion coefficient of the electroactive species in electrolytes increased, giving enhanced current densities. Fig. 1. Linear sweep voltammetry of PVA-LiCF3SO3 complexes. Scan rate: 1mV/s. (a) PVA:salt=50:50, (b) PVA:salt=40:60, (c) PVA:salt=20:80 |
| 저자 | 조윤경, 정수경, 조남주 |
| 소속 | 부산대 |
| 키워드 | solid polymer electrolyte; poly(vinyl alcohol); fast cationic transport process |
