Acta Phys. -Chim. Sin. ›› 2007, Vol. 23 ›› Issue (07): 1136-1140.doi: 10.3866/PKU.WHXB20070734

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Preparation and Characterization of the Composite Alkaline Polymer Electrolyte Based on PVA-Bentonite-KOH-H2O

ZHANG Ji-Fu; SANG Shang-Bin; WU Qiu-Mei; LIAO Yu-Gen   

  1. College of Chemistry and Chemical Engineering, Central South University, Changsha 410083, P. R. China
  • Received:2007-01-18 Revised:2007-03-28 Published:2007-07-03
  • Contact: SANG Shang-Bin


A series of composite alkaline polymer electrolyte membranes composed of poly(vinyl alcohol) (PVA), potassiumhydroxide (KOH), bentonite, and water were prepared by a solution casting method. The composite alkaline polymer electrolytes of PVA-bentonite-KOH-H2O were characterized by XRD, SEM, and CV technologies. The influence of bentonite on electrical conductivity of the composite membrane was studied. The results indicated that the bentonite had dual effects on the conductivity of the composite membrane; on one hand, it could decrease the conductivity of composite membrane by blocking the ion transfer tunnel in the PVA polymer structure, on the other hand, it improved the conductivity by increasing the KOH content in the composite electrolyte and forming a highly conductive defective layer on PVA-bentonite phase interface. However, in the system, when the water mass fraction was relative lower, the conductivity of the composite electrolyte system had a maximun value, while at a more higher water content w(H2O)=65%, the conductivity of the systemincreased linearly. The highest electrical conductivity reached 0.110 S·cm-1 at roomtemperature. XRD patterns revealed the amorphous structure of PVA in the composite membrane with appropriate mass ratio; SEM test confirmed that the bentonite-blending composite membrane contained a lot of micro-tunnels; cyclic voltammetry measurement demonstrated that composite alkaline polymer electrolyte membrane had a wide electrochemical stable window (about 2.0 V).

Key words: Alkaline polymer electrolyte, PVA, Bentonite, Conductivity, Electrochemical property


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