锂离子电池正极材料LiMnPO_4的合成与性能  

Synthesis and Performance of LiMnPO_4 Used as Cathode Material for Lithium Ion Batteries

作　　者：常晓燕[1] 王志兴[1] 李新海[1] 匡琼[1] 彭文杰[1] 郭华军[1] 张云河[1] 

机构地区：[1]中南大学冶金科学与工程学院,长沙410083

出　　处：《物理化学学报》2004年第10期1249-1252,共4页Acta Physico-Chimica Sinica

基　　金：国家自然科学基金(50302016)资助项目~~

摘　　要：对反应物与中间产物进行球磨,采用固相反应法分别在600℃和800℃合成了掺碳的橄榄石型LiMnPO4.通过XRD表征样品的晶体结构,采用SEM观察样品的微观形貌,利用电化学手段测试样品的充放电性能.结果表明,在对反应物球磨24h、中间产物球磨12h的条件下,在600℃烧结的样品含有杂相和烧结密实的大块状物.而在800℃下烧结可形成纯橄榄石结构的LiMnPO4,但颗粒较大.上述两种样品的电化学测试表明,它们难以充放电.而在反应物球磨36h、中间产物球磨24h的条件下,600℃烧结得到物相较纯,样品的粒径小且均匀,约100～200nm,首次放电容量接近100mAh·g-1.本研究表明,反应物或中间产物的混合程度以及烧结温度的选择是获得具有可逆充放电性能的纯橄榄石结构LiMnPO4的重要因素.Olivine LiMnPO4 was synthesized at 600 degreesC and 800 degreesC by the method of solid-state reaction combining with the addition of carbon black and ball-milling of reagents and precursors. Structure, surface morphology and charge/discharge performance of LiMnPO4 Were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM), and electrochemical measurement, respectively. Sample synthesized at 600 degreesC by ball-milling of reagents for 24 h and precursors for 12 h contains impurities and large, densely sintered blocks. Pure olivine LiMnPO4 with large particle size is obtained at 800degreesC by the same ball-milling process. It is shown that these materials can't charge or discharge effectively in the electrochemical tests. On the contrary, sample prepared at 600degreesC by ball-milling of reagents for 36 h and precursors for 24 h presents pure phase with small and almost identical particles size (about 100 similar to 200 nm). The initial discharge capacity of this sample is approximately 100 mAh . g(-1). Mixing of the agents and the precursors and the choice of sintering temperature are two important factors to obtain pure olivine LiMnPO4 with reversible charge-discharge capacity.

关 键 词：锂离子电池 正极材料 橄榄石结构 锂锰复合氧化物 合成 电化学性能 

分 类 号：TM912[电气工程—电力电子与电力传动]