前期掺杂BC对LiFePO_4/MWNTs性能的影响

Effect of BC doping during previous stage on properties of LiFePO_4/MWNTs composite cathode materials

以竹材为原料,在高温Ar保护下制备了竹炭(BC),并将其掺杂到LiFePO4/MWNTs复合材料中,用XRD、SEM、恒流充放电、循环伏安和塔菲尔曲线测试技术研究了前期掺BC对LiFePO4/MWNTs性能的影响。结果表明:掺杂3%质量分数BC时,LiFePO4/MWNTs/BC样品具有最好的电化学性能,以0.1 C循环的首次放电比容量高达169 mAh/g,11次循环后容量保持率为87.0%,并且随着放电倍率的增加,容量衰减变快;0.2 C和0.5 C放电时,放电比容量降为143 mAh/g和132 mAh/g,然而循环稳定性较好,11次循环后,容量保持率分别为94.4%和93.9%。

Bamboo charcoal （BC） was prepared by high-temperature in Ar gas with bamboo as raw materials and doped to LiFePOJMWNTs composite. The effects of BC during the previous stage on the electrochemical properties of LiFePOJMWNTs/BC composite were investigated by XRD, SEM, galvanostatic charge-discharge, cyclic voltammetry （CV） and Tafel curves. The results show that the as-prepared sample （doped 3% BC） delivers 169 mAh/g at 0.1 C and the capacity retention reaches to 87.0% after 11 cycles. Furthermore, with the increasing of discharge rate, the capacity deteriorates faster. Its discharge specific capacity are only 143 mAh/g and 132 mAh/g at 0.2 C and 0.5 C, and the capacity retention rate are 94.4% and 93.9% at the 11t＂ cycle, respectively.