Impedance spectroscopy of PEO-lithium triflate confined in nanopores of alumina membranes

Abstract

Abstract. Polymeric electrolytes are very useful for their technological applications in different electrochemical devices such as batteries, electrochromic devices, smart windows, etc. One of the most studied solid electrolyte system is PEO (poly-ethylene oxide) complexed with various lithium salts. A limitation of this polymer electrolyte is low ionic conductivity. However, nanoscale manipulation of the solid polymer electrolyte has the potential to address this issue. This work discusses how it is possible to increase the PEO conductivity when this polymer is contained in nanostructures, specifically nanopores. The nanostructures used are alumina filtration membranes (thickness = 6 ~tm, diameter = 13 mm) with three different pore sizes 0.02 p~m, 0.1 ~tm and 0.2 p~m. Electrochemical characterization has been performed with an HP4194A Impedance/Gain phase analyser and Solartron 1260 Impedance/Gain phase analyser. The former instrument tests these films at a high frequency (from 100 Hz to 40 MHz) while the later at low frequency (from 1 Hz to 1 MHz). From these experiments, it has been determined that two regions of ion conduction exit. One is conduction through the bulk polymer electrolyte in the pores while the other is an interfacial conduction at the interface between the pore walls and the PEO electrolyte. The conductivity of the PEO is increased when confined in these nanostructures.

Crystallinity and order of poly(ethylene oxide)/lithium triflate complex confined in nanoporous membranes

“…This behavior has been seen in previous studies conducted on electrolytes confined in nanopores, and these features were attributed to bulk and interfacial regions [43]. The low frequency feature is not present in all data collected while the high frequency semicircle is present in all samples and at all temperatures.…”

Plasticizers and Salt Concentrations Effects on Polymer Gel Electrolytes Based on Poly (Methyl Methacrylate) for Electrochemical Applications

“…Gel polymer electrolytes in different configurations have been proposed in electrochromic devices and lithium batteries: gel, blend and ionic liquid [ 11 , 12 , 13 ]. To improve the specific conductivity of the polymer electrolytes, the confinement of polymer electrolytes in the nanopores of alumina membranes has also been investigated [ 14 ].…”

The Integration of Nanoscale Techniques for an Improved Battery Technology

“…An interesting area of work has investigated the use of interpenetrating networks where one phase is the ion conducting phase while the other non-conducting phase can provide mechanical reinforcement that promotes the dimensional stability of the formed polymer electrolyte composite [115][116][117][118][119][120][121][122][123][124][125][126][127][128][129][130][131]. In many cases, the non-conducting phase appears to enhance conduction [117,118,126,127,131] as is observed for micro and nanoscale filler materials.…”

“…In many cases, the non-conducting phase appears to enhance conduction [117,118,126,127,131] as is observed for micro and nanoscale filler materials. Recent work has involved PEO-complex polymer electrolyte confined in the nanopores of structurally well-defined membranes having channels that are parallel to each other and are perpendicular to the surface of the membrane [94,117,[126][127][128]131]. This channel geometry is intriguing for several reasons.…”