选择性溶出法制备水铁矿的电化学性能研究

Study on Preparation and Electrochemical Property of Ferrihydrite by Selective Extraction Method

以镁铁类水滑石化合物为前驱体,利用选择性物相溶出法制备了2L-型水铁矿。对产物进行了XRD和N2吸附脱附等表征,并研究了产物的电化学性能。结果表明:这种多孔的2L-型水铁矿具有比表面积大、介孔分布均匀等优点;在电压区间1.5～4.2V,电流密度0.318mA/cm2的测试条件下,以Mg/Fe=2(物质的量之比)的水滑石为前驱体制得的样品性能最佳,初始放电比容量在203.8mAh/g,经过14次充放电循环后的放电比容量稳定在100mAh/g上。

2L-ferrihydrite was prepared from Mg/Fe hydrotalcite-like compound precursor （MgFe-CO3- LDH） by a selective extraction method. The characterization of the product by means of XRD and N2 adsorption-desorption indicated that the 2L-ferrihydrite possessed large specific surface area and uniform pore distributions in mesopore regions. The electrochemical property of the 2L-ferrihydrite as the cathode of lithium ion batteries was also investigated. The results indicate that the product synthesized from Mg/Fe hydrotalcite-like compound precursor with Mg/Fe = 2 showed the optimal electrochelnical property. The initial discharge capacities are 203.8 rnAh/g at a voltage range 1.5 - 4.2 V and a current density of 0. 318 mA/cm^2, and the discharge capacity is retained 100 mAh/g after 14 charge-discharge cycles.