| abstract |
A positive electrode active material, preparation method and lithium ion secondary battery thereof. The positive electrode active material is lithium iron phosphate, wherein the lithium iron phosphate is modified by graphene. The preparation method is provided to disperse the lithium iron phosphate and the graphene in water, to mix the two materials mentioned above uniformly by ultrasonic and agitation, and to dry the mixture to get the composite of lithium iron phosphate and graphene or graphene oxide before annealing at a high temperature, the lithium iron phosphate positive electrode active material modified by graphene be gained finally. The lithium ion secondary battery presents the advantages of greater capacity, better cycling performance when charging and discharging, longer life, higher stability when cycling than traditional modified lithium ion battery such as carbon-coated battery, battery doped with conductive high molecular weight polymer etc. |