Synthesis and characterization of vanadium pentoxide-polymer electrolyte xerogel composites

Mixed conducting {dollar}rm Vsb2Osb5{dollar}-polymer electrolyte xerogel nanocomposites were synthesized by the sol-gel process. The {dollar}rm Vsb2Osb5{dollar} imparts electronic conductivity due to approximately 1% reduced vanadium introduced during the sol-gel process. Water introduced during the sol-gel synthesis imparts protonic conductivity. The polymer electrolyte imparts ionic conductivity.; The {dollar}rm Vsb2Osb5{dollar}((a-PEO){dollar}rmsb{lcub}n{rcub}LiCFsb3SOsb3rbracksb{lcub}x{rcub}{dollar}(a-PEO = {dollar}rm (CHsb2O)sb{lcub}0.1{rcub}(CHsb2CHsb2O)sb{lcub}0.9{rcub},{dollar} n = 10-24, x = 0.01-0.05) composites are anisotropic thin films ({dollar}sim{dollar}100 {dollar}mu{dollar}m), with the (a-PEO){dollar}rmsb{lcub}n{rcub}LiCFsb3SOsb3{dollar} intercalated between the {dollar}rm Vsb2Osb5{dollar} layers. The (a-PEO){dollar}rmsb{lcub}n{rcub}LiCFsb3SOsb3{dollar} reacts with {dollar}rm Vsb2Osb5{dollar} when the composites are heated to 120{dollar}spcirc{dollar}C. Loosely bound water associated with {dollar}rm Vsb2Osb5{dollar} xerogels is displaced by the (a-PEO){dollar}rmsb{lcub}n{rcub}LiCFsb3SOsb3{dollar}, but tightly bound water remains. Total conductivity perpendicular to the films is extremely low ({dollar}10sp{lcub}-8{rcub}-10sp{lcub}-9{rcub}{dollar} S/cm), but the ionic conductivity of (a-PEO){dollar}rmsb{lcub}n{rcub}LiCFsb3SOsb3{dollar} increases the perpendicular conductivity relative to polymer free {dollar}rm Vsb2Osb5{dollar} xerogels. The parallel conductivity is dominated by electronic conduction ({dollar}10sp{lcub}-3{rcub}-10sp{lcub}-4{rcub}{dollar} S/cm), which fits 1, 2 and 3-dimensional variable range hopping models equally well. As the relative humidity is increased, the parallel total conductivity of the composites unexpectedly decreases. The parallel electronic transference number of the composites continuously decreases with increasing relative humidity.; Bulk electrolysis was used to synthesize a reduced {dollar}rm Vsb2Osb5{dollar}((a-PEO){dollar}rmsb{lcub}10{rcub}LiCFsb3SOsb3rbracksb{lcub}0.05{rcub}{dollar} composite. The composite is structurally similar to the unreduced composites. Thermoelectric power data fit 1, 2 and 3-dimensional variable range hopping models equally well. The electronic conductivity of the reduced composite is not significantly higher than the unreduced composites.; The {dollar}rm Vsb2Osb5lbrack (MEEP)sb4LiCFsb3SOsb3rbracksb{lcub}0.05{rcub} (MEEP = (CHsb3OCHsb2CHsb2OCHsb2CHsb2O)sb2PN){dollar} composite exhibited a larger interlayer spacing than the {dollar}rm Vsb2Osb5{dollar}((a-PEO){dollar}rmsb{lcub}n{rcub}LiCFsb3SOsb3rbracksb{lcub}x{rcub}{dollar} composites. The parallel electronic conductivity and the perpendicular total conductivity of {dollar}rm Vsb2Osb5lbrack (MEEP)sb4LiCFsb3SOsb3rbracksb{lcub}0.05{rcub}{dollar} are nearly identical to those of {dollar}rm Vsb2Osb5{dollar}((a-PEO){dollar}rmsb{lcub}n{rcub}LiCFsb3SOsb3rbracksb{lcub}x{rcub}.{dollar} Variable temperature a.c. impedance measurements perpendicular to the {dollar}rm Vsb2Osb5lbrack (MEEP)sb4LiCFsb3SOsb3rbracksb{lcub}0.05{rcub}{dollar} films indicate that the perpendicular total conductivity is dominated by a hopping mechanism with a 0.2 eV activation energy. The perpendicular electronic transference number of {dollar}rm Vsb2Osb5lbrack (MEEP)sb4LiCFsb3SOsb3rbracksb{lcub}0.05{rcub}{dollar} is 1.0 in 0% relative humidity.