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Structure, electrical and optical properties of (PVA/LiAsF 6 ) polymer composite electrolyte films
Author(s) -
Varishetty Madhu Mohan,
Qiu Weiliang,
Gao Yuan,
Chen Wen
Publication year - 2010
Publication title -
polymer engineering and science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.503
H-Index - 111
eISSN - 1548-2634
pISSN - 0032-3888
DOI - 10.1002/pen.21437
Subject(s) - materials science , vinyl alcohol , absorption edge , band gap , polymer , electrolyte , composite number , analytical chemistry (journal) , ionic conductivity , absorption spectroscopy , composite material , optics , chemistry , organic chemistry , physics , optoelectronics , electrode
In this work, Li + ion conducting polymer composite electrolyte films (PECs) were prepared based on poly (vinyl alcohol) (PVA), lithium hexafluoro arsenate (LiAsF 6 ), and ceramic filler TiO 2 using solution cast technique. The XRD and FTIR spectra were used to determine the complexation of the PVA polymer with LiAsF 6 salt. The ionic conductivities of the (PVA + LiAsF 6 ) and (PVA + LiAsF 6 + TiO 2 ) films have been determined by the A.C. impedance measurements in the temperature range 320–440 K. The maximum conductivity was found to be 5.10 × 10 −4 S cm −1 for PVA:LiAsF 6 (75:25) + 5 wt% TiO 2 polymer composite film at 320 K. The calculation of Li + ion transference number was carried out by the combination of A.C. impedance and D.C. polarization methods and is found to be 0.52 for PVA:LiAsF 6 (75:25) + 5 wt% TiO 2 film. Optical properties such as direct energy gap, indirect energy gap, and optical absorption edge values were investigated in pure PVA and salt complexed PVA films from their optical absorption spectra in the wavelength range of 200–600 nm. The absorption edge was found at 5.76 eV for undoped film, while it is observed at 4.87 and 4.70 eV for 20 and 25 wt% LiAsF 6 doped films, respectively. The direct band gaps for these undoped and salt doped PVA films were found to be 5.40, 5.12, and 4.87 eV, respectively, whereas the indirect band gaps were determined as 4.75, 4.45, and 4.30 eV. POLYM. ENG. SCI., 2010. © 2009 Society of Plastics Engineers