In order to reduce the production cost of lithium iron phosphate(LiFePO4)cathode material for lithium ion batteries,appropriate fertilizer-grade ammonium phosphate was selected as the phosphorus source to prepare LiFePO4 cathode material.Firstly,using analytically pure NH4H2PO4 and(NH4)2HPO4 as different phosphorus sources,FePO4 precursor was prepared by in-situ polymerization-coprecipitation method,and LiFePO4/C was prepared by carbothermal reduction method.The properties and performance of the prepared LiFePO4/C were studied by XRD,SEM,FTIR,nitrogen adsorption-desorption test and electrochemical test.The results showed that the LiFePO4/C material prepared with NH4H2PO4 as the phosphorus source has better electrochemical performance and higher tap density.The initial discharge specific capacity at 0.1 C is 150.86 mAh/g.The discharge specific capacities at different rates were 150.86(0.1 C),146.20(0.2 C),138.93(0.5 C),130.35(1 C),118.83(2 C),101.48(5 C)mAh/g,respectively,and the tap density was 1.02 g/cm3.Therefore,NH4H2PO4 is more suitable as a phosphorus source to prepare LiFePO4 cathode material.The initial discharge specific capacity of LiFePO4/C prepared with fertilizer grade NH4H2PO4 as phosphorus source is 82.60 mAh/g,and after preliminary removal of impurities the initial discharge specific capacity reaches 130.63 mAh/g.
ammonium dihydrogen phosphatediammonium hydrogen phosphatelithium iron phosphatecathode material
万方数据
维普
