双碳源在LiFePO_4/C微波固相合成中的协同效应

The synergistic effect of dual carbon source on microwave synthesis of LiFePO_4/C

以Li2CO3,FeC2O4·2H2O和NH4H2PO4为前驱体,分别以葡萄糖和葡萄糖/乙炔黑为碳源,利用微波加热合成了LiFePO4/C正极材料.用X射线粉末衍射(XRD)和扫描电镜(SEM)对材料进行了表征,用四探针法测定了材料的电导率.研究了碳源与微波温度对材料微结构和电化学性能的影响,发现由于乙炔黑的协同效应,用双碳源在600℃反应即可得到最佳电化学性能的LiFePO4/C,而仅用葡萄糖作碳源反应需要在较高温度(如700℃)下进行.

LiFePO4/C cathode materials were synthesized in a microwave furnace with a mixture of Li2 CO3, FeC2 O4 · 2H2O and NH4H2PO4 as precursor, and a certain amount of glucose and glucose/acetylene black as carbon sources, respectively. The materials were characterized by X -ray powder diffractions （XRD） and scanning electron microscopy （SEM）, and the conductivities were measured by a four point probe technique. The effect of acetylene black and temperature on microstructure and properties were investigated, which indicates that high performance LiFePO4/C can be obtained at 600 ℃ with the dual carbon source due to the synergistic effect, while the synthesis without acetylene black has to be performed at 700 ℃.