水热法以磷铁制备电池级磷酸铁的研究

摘要

Ferro-phosphorus,phosphoric acid and nitric acid were used as raw materials to prepare the battery-grade iron phosphate by hydrothermal method.The products were characterized by SEM,XRD,FTIR,TG-DSC and electrochemical testing.The influences of concentration of nitric acid,reaction temperature,reaction time and concentration on the properties of product were studied.The results indicated that the product is ferric orthophosphate and it contains a variety of trace mental elements,which effectively utilizes trace elements in ferro-phosphorus,improving the electrochemical properties of iron phosphate and lithium iron phosphate under a certain experiment condition.Simultaneously,by using the hydrothermally produced FePO4 · 2H2 O,LiFePO4/C can be synthesized through high temperature solid state method,which possesses a great electrochemical property with an initial discharge capacity of 148.9 mAh/g.%采用水热法,以磷铁、磷酸、硝酸为原料制备电池级磷酸铁,并利用扫描电镜(SEM)、XRD、红外光谱(FTIR)、TG-DSC以及电化学测试等手段,表征产品的形貌、晶体结构、分子结构和电化学性能,研究了反应过程中硝酸浓度、反应温度、时间及体系浓度对产品性能的影响.实验结果表明:以磷铁为原料,用水热法在一定实验条件下制备的FePO4·2H2O产品为正磷酸铁,且产品中含有多种微量金属元素,这有效利用了磷铁中的微量元素,改善了磷酸铁及后续制备的磷酸铁锂的电化学性能.以此为原料通过高温固相法合成的LiFePO4/C的首次放电容量为148.9mAh/g,具有良好的电化学性能.