Metal(ii) complex based on 5-[4-(1H-imidazol-1-yl)phenyl]-2H-tetrazole: the effect of the ligand on the electrodes in a lead-acid battery†
Abstract
Based on 5-[4-(1H-imidazol-1-yl)-phenyl]-2H-tetrazole (HL), three metal(II) complexes formulated as PbL2(H2O) (1) and ML2(H2O)4·2H2O (M = Ni 2 and Co 3) were synthesized and structurally characterized by single-crystal X-ray diffraction. A stable mononuclear metal(II) fragment was observed in the three complexes. The cyclic voltammograms (CVs) of complex 1 were investigated. In 0.5 M H2SO4 aqueous solution with and without the HL ligand, the Pb (or PbO2) electrode showed a similar electrochemical response but with less redox current in the presence of HL, which is most likely due to the formation of the Pb(II) complex upon the addition of HL, and it probably can decrease the redox rates of the two electrodes to some extent. The galvanostatic charge–discharge plot of the lead-acid battery shows a longer discharge time in the presence of HL. After CV or charge–discharge cycles, the Pb electrode consists of Pb and PbSO4 but with a lower PbSO4 content upon the addition of HL.