Influence Of Composite Modified Negative Carbon Materials On The Performance Of Lead-acid Battery

Lead-acid battery has been widely used in daily life and industrial production.However,there were still some problems which were very difficult to resolve,such as the sulfation of the negative active materials and short cycle life etc.Different treatment approaches,different kinds of carbon materials and different proportions of carbon materials added in the negative plates and the corresponding influence factors on the performance of the battery were investigated in the present paper.The Dipping-thermodecomposition technique was put forward to preparing modified activated carbon,which was added in the negative active materials.Various kinds of influence factors on the performance of lead acid battery had been investigated systematically.The results of EDS detection of modified activated carbon presented that there were high proportion of lead element in the modified activated carbon,which illustrated that PbO and Pb particles had already been attached to the surface or the pores of activated carbon through present methods.It was also identified that different phases of lead oxide carbon hydrated compounds were present according to XRD patterns of modified activated carbon.The battery added with activated carbon which was treated with HNO3-Pb(NO3)2 solution had the highest discharge capacity compared with the blank battery and the battery added with activated carbon treated with NaOH-Pb(NO3)2 solution.Furthermore,the battery added with activated carbon which was treated with HN03-Pb(N03)2 had best deep cycle life compared with the battery provided by one famous company.Expanded graphite(EG) which was a kind of new additive was added in the negative active materials together with a certain proportion of activated carbon.Various kinds of influence factors on the performance of lead acid battery were analyzed.The SEM images of EG showed that its particle size was 5?10?m and its overall structure was in irregular shape.It was found that some flocculent materials were distributed on the surface of paste added with EG compared with the paste without any additives.It could be concluded that the flocculent materials were EG based on the results of XRD analysis.Besides,characteristic peaks of AC and EG could be observed according to XRD patterns of the paste samples added with 1%AC and 1%AC,1%EG,which illustrated that AC and EG had been distributed in the active materials uniformly.The cyclic voltammogram of the corresponding small powder electrodes presented regular peaks of the electric double layer capacitance.It was shown that the utilization of negative active material has been increased with the increase of EG proportion according to the results of utilization test of negative active materials for the test battery.Different proportion of activated carbon were added in the negative active materials and several factors influencing the performance of test battery were investigated.It illustrated that activated carbon could be distributed uniformly on the surface of the paste based on the results of XRD and SEM analysis.The typical oxidation current peak of Pb to PbSO4 and the discharge of electric double layer capacitance were observed from linear sweep voltammograms of the corresponding small powder electrodes in 1.20 g · mL-1H2SO4 solution.Furthermore,it was found that the charging voltage of the battery added with 0.3%and 0.5%activated carbon was lower than that of the blank battery,which illustrated that the proportion of activated carbon could make the negative electrode potential not reach the hydrogen evolution potential.