Synthesis And Electrochemical Properties Of LiFePO₄/CNTs Composite

LiFePO4has considered as a promising cathode material for power lithium-ionbatteries due to its advantages of being aturally abundant, nontoxic, inexpensive, highcapacity, stable voltage plateau. But the pristine material only have one-dimensionalchannel for lithium ion migration and poor electric conductivity. This restrict the rateperformance of LiFePO4. So the materil just cannot promote because of the defect.Synthesis of nano-LiFePO4materials by homogeneous precipitation and add CNTswere mainly studied to improve the electrochemical performance of LiFePO4.1. The FePO4precursors were prepared by homogeneous precipitation. To findthe optimal reaction conditions by control the reaction temperature, the reaction timeand the category of oligomeric surfactant. Synthesis the LiFePO4/C by the optimalreaction conditions, and the material exhibited the best electrochemical performanceand the optimum microstructure. The material delivering a discharge capacity of147.879mAh/g,134.975mAh/g at rates of0.1C and1C. The discharge capacitymaintains97.6%(0.1C) respectively after100cycles, indicating its great cyclestability.2. Synthesis of FePO4/CNTs precursors by homogeneous precipitation. ThenLiFePO4/CNTs/C materials were synthesized by heating the precursors ofFePO4/CNTs and quimolar Li2CO3under Ar flow. The influences of different amoutof CNTs on the performance of LiFePO4/CNTs/C were investigated. The resultsshowed that the sample with2.02%CNTs displayed the best electrochemicalproperties. The material delivering a discharge capacity of155.131mAh/g、140.847mAh/g、112.197mAh/g at rates of0.1C,1C,10C. he discharge capacitymaintains99.68%(0.1C) respectively after100cycles,74.8%(1C) after1200cycles.