Controllable synthesis of Li3PO4 hollow nanospheres for the preparation of high performance LiFePO4 cathode material

Lithium phosphate hollow nanospheres were prepared in a membrane dispersion microreactor using aqueous phosphoric acid and lithium hydroxide solutions as reactants. The influences of reactant flow rate ratio and temperature on the purity and morphology of the prepared nanospheres were investigated using X-ray diffraction, scanning electron microscopy, and transmission electron microscopy. The results showed that nanospheres prepared in the continuous flow condition had a hollow interior structure with high crystallinity. A possible mechanism for the formation of this hollow structured Li3 PO4 was also pro- posed. Using Li3 PO4 hollow nanospheres as the precursor, LiFePO4 hollow nanospheres were successfully synthesized via a solvothermal route in ethylene glycol. After coating with carbon, the LiFePO4/C hol- low nanospheres exhibited excellent electrochemical performance, especially at high rates, and could discharge124 mAh/g at 10 C, and even 98 mAh/g at 40 C.

介孔碳纳米微球在锂离子电池中的应用

将介孔碳纳米微球粉末与磷酸铁锂(LiFePO_4)、石墨混合(介孔碳含量为8%)作为电池的正负极材料,组装锂离子电池。添加碳纳米微球后,电池的可逆性和比容量均优于未添加的,尤其在大电流9.0 A充放电时,充电电压平台约低0.25 V;充放电效率高出约88.5%;输出容量与放电电流为0.8 A时的比值高约15%。在低温0℃、-10℃和-20℃放电时,添加碳纳米微球的电池输出容量与额定容量的比值比未添加的分别高12.4%、14.9%和16.7%。