Lithium Ion Conducting Polymer Electrolytes Research Articles

Polymer electrolyte based solid state redox supercapacitors with poly (3-methyl thiophene) and polypyrrole conducting polymer electrodes

Types I and II solid state redox supercapacitors have been constructed using polypyrrole (pPy) and poly (3-methyl thiophene) (pMeT) conducting polymer electrodes with lithium ion conducting polymer electrolyte poly(ethylene oxide) (PEO)-LiCF3SO3 plasticised with poly (ethylene glycol) (PEG). The performance of the capacitors has been characterised by a.c. impedance, linear sweep voltammetry, galvanostatic charge-discharge methods and long term cycling tests. The asymmetric type II capacitors with p-doped pPy and pMeT electrodes give a capacitance value ∼ 2 mF cm−2 (equivalent to 18 Fg−1 of the total mass of the electrodes) and can be charged up to the voltage of 1.7 V. The symmetric type 1 capacitors of the configuration pPy | polymer electrolyte | pPy and pMeT | polymer electrolyte | pMeT show comparable values of capacitance but they are limited to the working voltage of <1.0 V.

Studies on all solid state electric double layer capacitors using proton and lithium ion conducting polymer electrolytes

Proton and lithium ion conducting polymer electrolytes, based on poly(vinyl alcohol)–H3PO4 and poly(ethylene oxide)–LiCF3SO3 plasticised with poly(ethylene glycol), have been used in the construction of electric double layer capacitors with both high density graphite sheet and activated carbon fabric electrodes. The polymer electrolytes have room temperature ionic conductivities (ca. 10−4–10−3 S cm−1) that make them suitable for use in thin-film form in devices. The performance characteristics of the capacitors have been studied using impedance analysis, linear-sweep voltammetry and charge–discharge methods. The supercapacitors based on the activated carbon fabric have characteristically large values of overall capacitance of 360–470 mF cm−2 [equivalent to single electrode capacitance 70–90 F (g carbon)−1] with the proton conducting electrolyte. Systems based on lithium ion conducting polymer electrolytes, however, have a much lower capacitance of ca. 20 mF cm−2 (equivalent to a single electrode capacitance of ca. 4 F g−1).

Properties and applications of lithium ion-conducting polymers

The electrochemical properties of lithium ion-conducting polymer electrolytes are discussed in terms of mechanical properties and of ionic conductivity at low temperature. The applications of these electrolytes in solid-state batteries and electrochromic devices are illustrated and evaluated.

Applications of multivalent ionic conductors to polymeric electrolyte batteries

The feasibility of solid state cells based upon lithium ion conducting polymer electrolytes has been demonstrated. In the present paper a preliminary investigation of sodium and magnesium ion conductors in polymer electrolyte cells is summarized. Cell types were Li|V 6 O 13 , Na|V 6 O 13 , and Mg|V 6 O 13 with polymer electrolytes based on polyethylene oxide and salts of the anode element.