| In order to cope with the excessive consumption of the earth's oil resources and the protection of the environment,the development of new energy vehicles and clean energy has become a global research hotspot.In the new energy vehicles and energy storage,power batteries and energy storage batteries become the bottleneck of its development.In recent years,due to the lead carbon battery overcomes the disadvantages of the traditional lead-acid batteries in hybrid cars,electric vehicles and energy storage applications and retains the advantages(high security,high recovery and low price)of lead-acid battery.So lead carbon batteries were applied in the filed of power battery and energy storage batteries.The carbon materials have a great influence on the performance of the lead carbon battery,such as under the high rate partial state of charging(HRPSoC)the cycle performance,rate and charging accept ability.Therefore,it is of great significance to study the carbon material type and the proportion of the lead carbon battery.In this paper,different carbon materials were tested for linear cyclic voltammetry,and activated carbon(AC)with high hydrogen evolution potential was selected for use in lead-carbon batteries.Different contents of AC were used in lead carbon batteries.We systematically discussed the effect of different proportions of AC on the performance of leaded carbon batteries.When the amount of AC is 1.0 wt%,the cycle-life under HRPSoC condition was 6810,the utilization ratio of negative active materials was raised to 70.7% and the charge acceptance increased to 8.7.This is because the second phase formed AC can effectively separate the lead sulfate crystals,increased the plate porosity,and small granular AC embedded into lead sulfate crystals,even the lead frame,improve the electrical conductivity,suppresse the irreversible sulfation of the negative active material(NAM).Moreover with the increase of contents of AC,hydrogen evolution of negative plates is more serious.In this thesis,different contents of graphene nanosheets(GNs)were used in lead carbon batteries.As a quasi-two-dimensional material,GNs have big specific surface area,good conductivity,good flexibility and good dispersibility,and can be uniformly dispersed into negative active materials to improve the performance of lead-carbon batteries.When the contents of GNs is 0.9 wt%,the cycle-life under HRPSoC condition was improved by more than 370% from 2826 to10527,the utilization ratio of negative active materials was raised to 63.7% and the charge acceptance increased to 8.68.This is because the combination of GNs with lead is good,and GNs can be used as a skeleton of the negative active material to establish a three-dimensional conductive structure,which promotes the transfer of electrons and inhibits the irreversible sulfation of the negative active material.In this paper,in situ chemical deposition of lead grains on GNs(GNs@Pb)composites are synthesized by chemical deposition and heat treatment,Pb grains can be evenly distributed on the surface of GNs,Pb grains are irregular plane circular and the size of Pb grains are 50~100 nm.The proportion and the hydrogen evolution overpotential of GNs@Pb are bigger than GNs.GNs@Pb composite materials were applied to the lead carbon batteries,under HRPSoC state the cycle life was up to 14466,the rapid discharge capacity at 20I20 was 2.35 Ah,containing GNs was 1.81 Ah.Lead carbon batteries with GNs@Pb showed excellent electrochemical performance,mainly due to its high hydrogen evolution overpotential and larger proportion,it improves the charge efficiency of batteries,can be batter combined with negative active material,increases the electrical conductivity of negative active materials,inhibits the negative sulfation and improves the performances of batteries. |
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