Lead ion and tetrabutylammonium bromide (TBAB) have been testified as inhibitors of spongy zinc electro-growth from flowing alkaline zincate solutions. To assess the efficacy of the two additives, current–time technique using potentiostatic electro-deposition, scanning electron microscopy and cycling test were undertaken. The results show that the growth of spongy zinc in flowing alkaline zincate solutions can be effectively inhibited by the addition of 10−4 M Pb(II) or TBAB at the cathodic potential (η =−100mV), respectively. But, the dual addition of 10−4 M Pb(II) and 5×10−5 M TBAB produces more effective suppression on spongy zinc growth. Obvious synergistic effect of Pb(II) and TBAB on the inhibition of spongy zinc deposits is found. From the charge/discharge cycling tests of the single flow Zn–Ni test cells, it is shown that the rechargeability of Zn anode is highly improved by the mixed introduction of 10−4 M Pb(II) and 5×10−5 M TBAB.