Physicochemical and electrochemical study of lead acid battery positive active mass (PAM) modified by the addition of bismuth

This study attempts to discuss the influence of Bi alone and its combination with Sb and Sn on the electrochemical performance of the PAM of lead acid batteries. The different additives were added in the electrolyte as cations. PAMs were prepared by electro formation of cured battery plates in the presence and absence of a dopant (non-doped sample ND). The results from different analyses showed that bismuth alone gives a remarkable improvement of the capacity. The highest performance of PAM is obtained when bismuth is mixed with tin together as dopants. The incorporation of bismuth and tin cations leads to an increase of the quantity of structural water in PAM. This increases the hydrated and amorphous zones within the PbO2 particles and leads to an improvement of the electrochemical capacity.