Effect of Electrode Additives on the Electrochemical Behaviour of Porous Cadmium Hydroxide Electrode for Alkaline Secondary Battery System

摘要

Cadmium secondary systems have high energy density,power density,long cycle life,rugged physical structure and good low temperature performance.Cadmium secondary systems are mainly used in Electric vehicles as well as in military and commercial aircraft.The main problems of cadmium secondary systems are passivation,dissolution and precipitation of the oxidation products of cadmium in the electrolyte.The present study deals with the effect of additives added to the cadmium hydroxide electrode for increasing the discharge capacity and for minimizing self-discharge.The influence of individual additive in various concentrations of Pb(NO_3)_2,Cu(NO_3)_2,Mg(NO_3)_2 and ZnSO_4 on the reversibility of the redox couple is examined by cyclic voltammetric technique.The effect of discharge rate on the cyclic efficiency and ageing behaviour are also discussed.The self-discharge currents at both room temperature and elevated temperatures are determined by potentiodynamic polarization method.Impedance technique is also used to characterize the performance of the porous cadmium electrodes.Based on these studies,a suitable and optimum composition for the electrode fabrication is suggested.