PEG固相还原制备LiFePO_4及材料的电池性能

Synthesis of Olivine LiFePO_4 via Solid State Method Using PEG and its Electrochemical Performance

本文首次采用PEG固相还原Fe2O3成功地制备了LiFePO4锂电池用正极材料。通过XRD、SEM表征了材料的相态和形貌,采用恒电流充放电法研究了材料的电化学性能。SEM图上可观测到材料呈现出微米球形团簇结构和蜂窝状的表面;XRD结果表明,晶相为橄榄石型磷酸铁锂。对电池的电化学测试表明,制备的LiFePO4材料表现出优良倍率性能和循环稳定性,在0.1 C和0.3 C下,放电比容量分别为139.9 mAh/g和127.5 mAh/g,30次循环后比容量没有衰减。这种以廉价铁盐Fe2O3的PEG固相还原制备,为锂电池正极材料LiFePO4低成本制备提供了新的方法。

LiFePO4 cathode materials were prepared using raw Fe2O3 by a solid state method with PEG as reductant. The crystal structure and the electrochemical performance were characterized by XRD, SEM, and electrochemical testing, respectively. The product is identified as well-ordered olivine structure of the LiFePO4 and has spherical grain and porous surface structure. Initial discharge capacities of 139.9 and 127.5 mAhg-a are achieved at the rate of 0.1 C and 0. 30 C, respectively. And almost no capacity loss can be observed after up to 30 cycles. This solid state synthesis using cheaper Fe2O3 and PEG provides a new and effective method for the low cost preparation of lithium-ion battery cathode material LiFePO4.