Optimisation of PVdF-based polymer electrolytes

The plasticized polymer electrolyte composed of polyvinylchloride (PVC) and polyvinylidene fluoride (PVdF) as host polymer, the mixture of ethylene carbonate and propylene carbonate as plasticizer, and LiCF 3 SO 3 as a salt was studied. The effect of the PVC-to-PVdF blend ratio with the fixed plasticizer and salt content on the ionic conduction was investigated. The electrolyte films reveal a phase-separated morphology due to immiscibility of the PVC with plasticizer. Among the three blend ratios studied, 3:7 PVC-PVdF blend ratio has shown enhanced ionic conductivity of 1.47×10 −5 S cm −1 at ambient temperature, i.e., the ionic conductivity decreased with increasing PVCto-PVdF ratio and increased with increasing temperature. A temperature dependency on ionic conductivity obeys the Arrhenius behavior. The melting endotherms corresponding to vinylidene (VdF) crystalline phases are observed in thermal analysis. Thermal study reveals the different levels of uptake of plasticizer by VdF crystallites. The decrease in amorphousity with increase in PVC in X-ray diffraction studies and larger pore size appearance for higher content of PVC in scanning electron microscopy images support the ionic conductivity variations with increase in blend ratios.

Section: Resultsmentioning

confidence: 80%

Section: Introductionmentioning

confidence: 99%

Ionic transport, thermal, XRD, and phase morphological studies on LiCF3SO3-based PVC–PVdF gel electrolytes

Vickraman

Aravindan

Selvambikai

et al. 2008

“…Since the viscosity of polymer electrolytes depends upon the weight ratio of polymer, KOH, and added zinc salt [19], the present study favors the addition of an optimum amount of 25% of zinc salt, irrespective of the type of films (B or C) being fabricated. On the contrary, higher concentration of zinc salts (30% and 35%) have exhibited lesser conductivity values (10 −3 ) and more specifically, if the salt concentration is higher than that of KOH (B1, B2, C1, and C2), the conductivity values are found to decrease accordingly.…”

Section: Resultsmentioning

confidence: 82%

Effect of mixed cations in synergizing the performance characteristics of PVA-based polymer electrolytes for novel category Zn/AgO polymer batteries—a preliminary study

Vatsalarani

Kalaiselvi

Karthikeyan

2008

Self Cite

Thin films of polymer electrolytes comprising of PVA and KOH (A) with and without the addition of zinc salts, viz., zinc acetate (B) and zinc triflate (C) as mixed cations were prepared via. solution casting method. The thermal stability and ionic conductivity of PVA-KOH solid polymer electrolyte (A) were improved by the partial substitution of KOH with zinc salts. Among the two salts, zinc triflate was found to improve both the physical as well as electrochemical properties of the PVA-KOH films more significantly than zinc acetate. An attempt to optimize the ratio of various components of polymer electrolytes, viz., polymer: KOH: zinc salt was also made, based on the dimensional stability and ionic conductivity values. Finally, the select category polymer film containing PVA-KOHzinc triflate (C) in an optimum ratio of 40:35:25 was deployed in coin cell fabrication and subjected to chargedischarge studies with a view to demonstrate the possible electrochemical reversibility characteristics. Based on the encouraging results obtained from the cycling study, C type films [PVA-KOH-zinc triflate] qualify themselves as potential polymer electrolytes for use in rechargeable Zn/ AgO polymer batteries.

“…However, the effect of added lithium salt can also not be neglected. Because, the PVdF homo-polymer electrolytes containing the same EC + PC as plasticizer are reported to exhibit en- tirely different values of conductivities in the range of 10 .5 to 10 "~ Scm 1 with a difference in the type of lithium salt added [13]. Hence, the imparted amorphous nature of the gel polymer electrolytes, is believed to have a marked effect, due to the addition of lithium salt also.…”

Section: Resultsmentioning

confidence: 99%

Performance evaluation of PVdF gel polymer electrolytes

Periasamy

Tatsumi²,

Kalaiselvi

et al. 2002

Self Cite

i.e., from 20 ~ to 65 ~ XRD and DSC studies were carried out to characterize the polymer films for better amorphicity and reduced glass transition temperature, respectively. The electrochemical interface stability of the PVdF based gel polymer electrolytes over a range of storage period (24 h -10 days)have been investigated using A.C. impedance studies. Test ceils containing Li/gel polymer electrolyte (GPE)/Li have been subjected to undergo 50 charge-discharge cycles in order to understand the electrochemical performance behaviour of the dimensionally stable films of superior conductivity. The observed capacity fade of less than 20% even after 50 cycles is in favour of the electrochemical stability of the gel polymer electrolyte containing 27.5% PVdF -67.5 % EC+PC -5% imide salt. Cyclic voltammetry studies establish the possibility of a reversible intercalationdeintercalation process involving Li § ions through the gel polymer electrolyte.