Discussion on the Behavior of Ag₂O added to Pressed-type Nickel Positive Electrode

Abstract

The addition of Ag20 was found to increase the availability of active material in the Positive plate (Ni (OH)2; 50, graphite; 35, polyethylene; 15) of pressed-type Ni-Cd storage battery and the authors studied the function of Ag20 on charge-discharge by means of current-potential curve obtained with Ag in aqueous pottasium hydroxide and atomic absorption spectrophotometry. The following mechanism was proposed;
(1) The discharge capacity of Ag2O is not contained in that of nickel electrode.
(2) Ag20 added to the positive plate changes into Ag by the reaction (Ag20 Ag) on discharging, and Ag changes into active Ag20 by the reactions (2 Ag + 2 0H- 2 AgOH + 2 eand 2 AgOH - Ag20 + H₂0) on charging. A part of this active Aga dissolves into electrolyte solution and dissociates according to the following equation: Ag20 Ag + Ag0-.
(3) Ag + will probably affects negative electrode and Aga- remaines in solution. But, amount of Ag dissolved from positive electrode, to which Ag20 is added in 10%, is very small even after 300 cycles.