Journal of Power Sources, 15 (1985) 93 - 100 93 zyxwvuts A ROTATING-DISK STUDY ON TEFLON-BONDED POROUS ZINC ELECTRODES A. DUFFIELD, P. J. MITCHELL and N. A. HAMPSON Chemistry Department, University of Technology, Loughborough, Leicestershire, LEI 1 3TU (U.K.) N. KUMAR and D. W. SHIELD Joseph Lucas Ltd., Group Research Centre, Solihull, West Midlands B90 455 (U.K.) (Received November 2,1984) summary Microcomputer-controlled, rotating-disk experiments have been carried out on Teflon-bonded porous electrodes fabricated from a 5% PTFE suspen- sion + ZnO. The effect of using 1% mercuric oxide as an additive on this type of electrode has been examined. Plots of z”’ us. w-l’* on electrodes containing mercuric oxide show intercepts through the origin for low over- potentials, inferring that quasi-reversible kinetics prevail. Introduction The possible use of zinc in a secondary electrode system, particularly if used in conjunction with nickel, is widely recognised as favourable due to its high gravimetric and volumetric energy densities and its relatively low cost. A recent paper [ 1] described a microcomputer-controlled rotating-disk electrode (RDE) experiment on solid and porous zinc electrodes which were free from additives. The porous zinc electrode reported was formed from Zn/ZnO paste in a O.OlM KOH solution. Most prototype commercial second- ary zinc electrodes incorporate additives to reduce factors such as dendritic growth and shape change, which limit the useful cycle life, and to raise the hydrogen evolution overpotential, thereby reducing zinc corrosion [ 2 - 51. Polymeric additives are often used as binders to help control the former factors: a common one in the zinc electrode (as well as other electrode systems) is PTFE [Z, 5 - 71. Amalgamation and incorporation of mercuric oxide is typically encountered to raise the hydrogen evolution overpotential [2 - 61, although under some circumstances this has been shown to have a deleterious effect upon cycle life due to shape change [ 61. Many RDE experiments have been carried out on solid planar zinc [ 8 - lo], but it appears that few equivalent studies on porous zinc, similar to those of McNeil [l], have been performed. Neither have these been 037%1753/851$3.30 0 Elsevier Sequoia/Printed in The Netherlands