Synthesis of porous nano/micro structured LiFePO_4/C cathode materials for lithium-ion batteries by spray-drying method

喷雾干燥法合成纳微多孔球形LiFePO_4/C锂离子电池正极材料（英文）

In order to enhance electrochemical properties of LiFePO4 （LFP） cathode materials, spherical porous nano/micro structured LFP/C cathode materials were synthesized by spray drying, followed by calcination. The results show that the spherical precursors with the sizes of 0.5-5 μm can be completely converted to LFP/C when the calcination temperature is higher than 500 ℃. The LFP/C microspheres obtained at calcination temperature of 700 ℃ are composed of numerous particles with sizes of -20 nm, and have well-developed interconnected pore structure and large specific surface area of 28.77 mE/g. The specific discharge capacities of the LFP/C obtained at 700 ℃ are 162.43, 154.35 and 144.03 mA.h/g at 0.5C, 1C and 2C, respectively. Meanwhile, the capacity retentions can reach up to 100% after 50 cycles. The improved electrochemical properties of the materials are ascribed to a small Li＋ diffusion resistance and special structure of LFP/C microspheres.

为提高LiFePO_4(LFP)正极材料的电化学性能,采用喷雾干燥结合煅烧工艺合成具有纳微结构和多孔结构的球形LFP/C材料。结果表明,当煅烧温度高于500°C时,粒径尺寸为0.5~5μm的球形前驱体可以完全转化为LFP/C材料。当煅烧温度为700°C时,所得的LFP/C微米球形颗粒是由大量粒径约为20 nm的颗粒及发育良好且相互连通的孔道组成,其比表面积为28.77 m^2/g。在0.5C、1C和2C的电流倍率下恒流充放电时,700°C时所得LFP/C材料的放电比容量分别为162.43、154.35和144.03 m A·h/g,且50次循环后的容量保持率达到100%。该材料所具有良好的电化学性能得益于其较小的Li+扩散阻抗和特殊的微观结构。