控制结晶法制备球形磷酸铁的团聚尺寸模型  

Agglomeration-size model of ferric phosphate spherical particle prepared by controlled crystallization

作　　者：张震[1] 蒲薇华[1] 任建国[1] 武玉玲[1] 何向明[1] 

机构地区：[1]清华大学核能与新能源技术研究院,北京100084

出　　处：《化学工程》2011年第8期20-24,共5页Chemical Engineering(China)

基　　金：国家"973"资助项目(2007CB209705);国家"863"资助项目(2009AA035201);清华大学自主科研资助项目(2009THZ08064)

摘　　要：磷酸铁是制备锂离子电池正极材料磷酸铁锂的主要前躯体之一,磷酸铁的形貌和粒度大小对磷酸铁锂材料的电化学性能有较大影响。为了更好地实现磷酸铁的可控制备,有效改善磷酸铁锂的电化学性能,文中采用硝酸铁和磷酸反应合成磷酸铁的液相结晶控制工艺,研究了反应结晶釜中反应物浓度、温度、搅拌速度与沉淀物颗粒粒径之间的关系,结果表明:沉淀物颗粒粒径随反应物的浓度的增大和反应温度的升高而减小,随搅拌速度的增加,粒径首先变大,当到达最大粒径后呈减小趋势。并且在团聚和破碎动力学的基础上通过经典的粒数衡算方程建立该反应的团聚尺寸模型,然后根据沉淀反应过程的实验数据获得所建模型的相关参数,通过模型计算值和实验值的比较验证了模型的可靠性。FePO4 （FP） is one of the main precursors for preparing LiFePO4 （LFP）as the Li-ion battery cathode. FP particle size and morphology is of crucial importance for electro-chemical performance of certain LFP battery. For the purpose of controlling the prepared FP spherical particle size and improving the elector-chemical performance of LFP, the influences of reactants concentrations, reaction temperature, agitation speed in the crystallization reactor on the agglomeration-size of the FP were investigated by using the liquid-phase controlled crystallization technology for preparing FePO4 by synthesizing ferric nitrate and phosphoric acid. The result shows that the size of spherical particles decreases with increasing the solute concentration or raising the reaction temperature; with the agitation speed increases, the particle sizes firstly grow bigger but then decrease when approaching a maximum size. The SEM observation reveals that these particles grow in spherical structure by agglomeration of primary small particles. Based on the agglomeration and disruption kinetics, an agglomeration-size model was derived through the population balance equation. The parameters of the model can be assumed from the data of the precipitation process, and the model is proven to be suitable for the description of agglomeration-size by comparing the model value with the experimental one.

关 键 词：锂离子电池 控制结晶法 球形磷酸铁 粒数衡算方程 团聚和破碎动力学 

分 类 号：TM912[电气工程—电力电子与电力传动]