Effect of mixed salts on the properties of gel polymeric electrolytes

Nonaqueous unimolar solutions of lithium perchlorate (LiClO4) and lithium trifluoromethanesulfonate or triflate (LiCF3SO3) in gamma-butyrolactone (gammaBL) mixed in (a) 1:1 and (b) 3:2 volume ratios yield mixed salt electrolytes with good conductivity performance with 925 approaching 10(-2) S cm(-1). Addition of 10 wt.% of poly(methylmethacrylate) (PMMA) to these liquid electrolytes manifests in producing highly viscous gel electrolytes with eta(25) in the range of 10(4)-10(5) cSt and sigma(25) greater than 10(-3) S cm(-1). Conductivity and viscosity studies reveal that PMMA plays an insignificant role in controlling the conduction mechanism in gel electrolytes, as they tend to retain the liquid-like behaviour. Also, the dimensional strength bestowed to gels by the polymer stimulates their use in electrochromic windows (ECWs), Inconsequential variation of a over the operational temperature range of an ECW renders them to be ideal candidates for the same. (C) 2002 Elsevier Science B.V. All rights reserved.