Magnesium rechargeable cells based on PVdF gel polymer electrolyte
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Date
2015
Journal Title
Journal ISSN
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Publisher
Uva Wellassa University of Sri Lanka
Abstract
Gel polymer electrolytes (GPEs) have received a keen interest as an excellent substitute for liquid
electrolytes due to anticipation of several advantages such as no leakage, no corrosion and easy
preparation. They are basically consisting of a salt solvent mixture encapsulated in a suitable
polymer matrix (Osman, et al. 2012). Due to the satisfactory conducting and mechanical
properties, they have been extensively considered as suitable electrolytes for various applications
such as rechargeable cells (Kumar et al, 2003) super capacitors (Tripathi et al, 2013) and
electrochromic devices (Wu et al, 2012). Plentiful of investigations have been carried out on
applications with Li based GPEs but now attention has been focused towards other cation based
GPE mainly due to some problems associating with lithium. As such non lithium based devices
have come forward getting more interest. Use of magnesium in place of lithium would be very
convenient as it possesses various important characteristics such as low cost, substantial
abundance, more stability than lithium and low toxicity (Pandey et al, 2011). This paper reports
about employing a magnesium based GPE in a magnesium rechargeable cell.
Methodology
Polyvinylidenefluoride (PVdF), Ethylene carbonate (EC), Propylene carbonate (PC) and
Magnesium trifluromethane sulfonate (MgTf) purchased from Aldrich were used as received.
Appropriate amounts of EC, PC and MgTf were mixed by magnetically stirring for about 2 hours.
Required amount of PVdF was added and stirring was continued for another 10 minutes. Then,
the mixture was heated at 120 C for 30 minutes. The resultant homogenous hot mixture was
pressed in between two well cleaned glass plates to obtain a thin GPE film. A circular pellet of
GPE was sandwiched in between two stainless steel (SS) electrodes and it was loaded inside a
brass sample holder which is sealed by means of an O ring. Diameter and thickness of the sample
were measured using a micrometer screw gauge. AC Impedance data were gathered by using
Metrohm Autolab M101 impedance analyzer in the frequency range 0.01 Hz - 0.1 MHz.
Temperature was varied from room temperature to 60 C by placing the sample holder inside a
Sibata glass tube furnace. Cyclic Voltammetry studies were performed by placing an electrolyte
sample in between two Mg electrodes. Three electrode electrochemical setup with a working
electrode, a counter electrode and a reference electrode was employed for the study. Scan rate
used was 5 mV/s. A cathode having Polypyrrole (PPy) polymerized in the presence of
Dodecylbenzenesulfonate (DBS) was prepared as reported before (Perera et al, 2008). The cells
in the configuration, Mg / GPE / PPy : DBS were assembled and their charge discharge behavior
was monitored. Cells were subjected to charge and discharge between the potential values 0.5 V
and 2.0 V. They were first discharged galvanostatically and then charged galvanostatically. When
the required potential has reached, further potentiostatic charge was done till the current drops to
10%.
Description
Keywords
Mineral Sciences, Materials Sciences, Electronic Engineering, Chemistry, Chemical, Chemical Engineering