Electrode for electrochemical generator - has layers of varying porosity and is used esp. in silver-hydrogen accumulator to obtain high capacity

摘要

The electrode consists of >=1 plate contg. a current collector and consisting of three layers of a porous active mass. The three layers have the same thickness, but the porosity of the middle layer is lower than that in the outer surface layers. In the pref. electrode, the thickness of the middle layer pref. has a ratio of 0.5-2:1 w.r.t. the thickness of each outer layer. The active mass is pref. silver, the porosity of the outer layers being 70-85%, whereas the porosity of the middle layer is 40-65%. The grain size in all three layers is pref. the same. The electrode is pref. made by compressing and sintering the middle layer, which is then coated with an active mass contg. a cellulosic gel binder, and sintered to form the outer layers. The prod. is pref. a positive electrode used with an alkali electrolyte and hydrogen as the negative electrode. A thick positive electrode can be made, but the electrolyte can penetrate the plate so there is no loss in battery capacity as compared with a battery using thin plates.