Prepn of (zinc) electrodes coated with e.g. PTFE - to provide gaps for gas escape during electrolysis

摘要

An improved process for prepg. electrodes for electro-chemical generators, the electrodes comprising a collecting zone made of a chemically inert conductor embedded in an electrochemically matrix comprising a metal (cpd.) and a partially crosslinked polymer, comprises (A) prepg. a satd. soln. of the polymer in water and adding 5-20% of a crosslinking catalyst, (B) adding at 50-100 degrees C 20-50 pts. wt. of the metal salt, based on polymer, the salt being water-soluble and compatible with the polymer, (C) casting the soln. into a mould contg. the collecting zone of the electrode to completely immerse the latter, (D) cooling the mould to at most -20 degrees C, (E) demoulding the cake and immersing it in an alkaline soln. satd. with the metal oxide, (F) washing the cake with cold water, (G) drying it at 20-60 degrees C and (H) pressing it under 2-10 bars/cm2. The improvement comprises depositing on each of the surfaces of the collecting (1) longitudinal strips (2) whic are non adherent to the electrochemically active part (5) of the electrode to create a gap (6) between part (5) and each strip (2). The process which is partic. applicable to Zn electrodes prevents diffusion of zincate ions and short-circuiting when the electrodes are used during electrolysis. The gaps allow free escape of gas, partic. H2, and thus eliminate formation of blisters on the electrode.