Chemical Modification And Performance Of Conductive Agents Used For Lithium Battery Cathode Material

Lithium iron phosphate battery has a lot of advantages that other Lithium-ionbattery cathode materials can not match, such as safety performance, low price,abundant sources of raw materials, and environmental friendliness. However, due topoor conductivity of the material itself, the battery has a larger internal resistance,resulting in poor performance of the material ratio, voltage platform and hightemperature performance. Usually by adding a conductive agent, the conductivity ofthe electrode can be improved. However, the uniform dispersion of the lithium ironphosphate conductive agent is still a problem, which severely restricts the furtherdevelopment of lithium batteries.This study is designed to conduct acid, alkali, strong oxidants modification on avariety of conductive carbon, and use the conductive carbon materials added single ormixed chemical modifications to produce button battery, as well as testing the batteryperformance and exploring the impact of conductive carbon on lithium iron phosphatecathode material. What’s more, the author uses the method of HUMMERs to producethe graphite oxide sol and try to deoxygenize into grapheme and compare thedispersion effect before and after oxidation.The experimental results showed that: the improvement of single-walled carbonnanotubes is more obvious than the improvement of multi-walled carbon nanotubes.When the annealing temperature of is370℃, it needs three hours, and ratios of mixedconductive carbon are as follows:2.5%SP、2.5%KS-6、1%CG-5and1%ST. Thebattery made by conductive carbon material which refluxes by10M of HNO3, H2SO4and strong oxidizing acid get the best result.1C discharge capacity of the batteryis137mAh·g-1and the cell efficiency is99%, voltage platform is3.24V.After scanning the graphite produced by the method of HUMMERs, SEM imageproves that oxidized graphite flake still exists as a superposition.However, thedistance between layer and layer has increased from0.5μm To1μm~1.5μm.The factproves that oxidized graphite slices will disperse better.