Application Of Addtives In Improving The Performance Of Positive Active Material Of Lead-Carbon Batteries

In today’s society,energy and environmental pollution have attracted wide attention from all countries.Protecting the earth’s environment,reducing exhaust emissions,developing new energy vehicles and non-fossil energy have become the common understanding of all countries in the world.In this context,electric vehicles and hybrid electric vehicles came into being.As the core part of the electric vehicle,the battery directly determines the performance of the electric vehicle.Therefore,looking for a battery with excellent performance is the primary task for the development of new energy vehicles.Lead-carbon battery is based on the traditional lead-acid battery,and the carbon material is partly or completely substituted for the negative active material spongy lead.Lead-carbon batteries retain the advantages of high recovery rate,high safety performance and low price of lead-acid batteries.It also overcomes the shortcomings of lead-acid batteries in the field of new energy vehicles and energy storage applications,such as electric vehicles and hybrid electric vehicles,and thus it has broad market prospects.At present,a great breakthrough has been made in the research of negative electrode of lead-carbon battery,and the improvement of negative cycle life leads to the problem of positive failure,caused by the softening and falling off of the positive active material（PAM）,more prominent.This paper mainly focuses on the research status of the failure mode and improvement method of the positive lead carbon battery.the effects of C_ZIF-8,SnO₂,In₂O₃ and In₂（SO₄）₃ on the electrochemical performance and cycle life of lead-carbon battery as PAM additive of lead-carbon battery,respectively,is compared with that of blank battery without additive.Electrochemical impedance,cyclic voltammetry,galvanostatic charge discharge and other experimental methods were used to study the PAM of lead-carbon batteries.First,the precursor ZIF-8 was prepared by the agitation method.The precursor were annealed at different temperatures,and the required samples C_ZIF-8-800℃,C_ZIF-8-900℃and C_ZIF-8-1000℃were obtained.The composition,surface morphology and pore structure of the samples were characterized by XRD,BET and SEM.The results show that the precursor ZIF-8 has the highest specific surface area after annealing at800℃,and the cubic eight-hedral structure is complete and the pore structure distribution is orderly.With the increase of annealing temperature,the cubic eight-hedral structure collapses,and the specific surface area decreases.When C_ZIF-8 is used as the PAM additive of lead-carbon battery,the electrochemical impedance of the battery can be reduced and the irreversible sulfation problem in the working process is inhibited.But only when the sample C_ZIF-8-800℃is added,the purpose of improving the cycle life of the lead-carbon battery can be achieved.The electrochemical impedance,initial capacity and cycle life of the battery are improved well when In₂O₃ is used as the PAM additive of the lead-carbon battery.Especially when the addition ratio is 0.3%,the cycle life of the battery is nearly 2.5times higher than that of the blank battery.But when In₂（SO₄）₃ is used as the PAM additive of lead-carbon batteries,the correlation test results show that only has a favorable effect on the reduction of the electrochemical impedance of the battery,and it has a negative effect on the initial capacity and the reversibility of the electrode reaction.The cycle life is reduced by nearly half compared with the blank battery when the addition ratio is 0.5%,1%and 1.5%.Although the cycle life increased slightly when the addition ratio is 2%,but on the whole,In₂（SO₄）₃ is not suitable as a PAM additive.When SnO₂ is used as the PAM additive of the lead-carbon battery,it can reduce the electrochemical impedance of the lead-carbon battery and have some advantages for the battery life.And when the proportion of SnO₂ in the PAM is 0.5%,the most ideal effect can be obtained.At this time,the first discharge time of the battery is 549min and the cycle times is 15801,which is much higher than the other doping proportion and the battery without SnO₂.