锂电池阴极材料V_2O_5常压干燥气凝胶的制备及离子输运特性

Preparation and ion transport properties of ambient pressure dried vanadium pentoxide aerogels as lithium battery cathode materials

以VO(OC_3H_7)_3、丙酮和水为原材料,采用溶胶-凝胶技术制备溶胶,通过溶剂替换工艺在常压下制备出了纳米多孔结构的V_2O_5气凝胶材料。使用扫描电镜(SEM)、透射电镜(TEM)、粉末X射线衍射(XRD)、BET分别观测和测试了V_2O_5气凝胶材料的形貌、晶态、气凝胶比表面积、孔径分布。结果表明:常压干燥制备的V_2O_5气凝胶呈比较规则的纤维状纳米多孔结构,比表面积达138.9m^2/g,平均孔径约为15nm,材料经300℃热处理后结晶。测试了V_2O_5气凝胶材料在不同电压下的交流阻抗谱(EIS),用等效电路进行了模拟,并对其动力学参数进行了分析和讨论。电化学测试表明,V_2O_5气凝胶首次放电容量为300.45mAh/g,可作为很好的锂离子电池阴极材料。

Ambient pressure dried V2O5 aerogels were prepared from VO（ OC3 H7 ）3 ,acetone and H20 by solgel method and solvent exchange process. The crystalstructure , crystalform structure and the aperture distribution of the V2O5 aerogels were investigated by SEM , TEM, XRD and BET. The experimental Results show that V2O5 ambient dried aerogels exhibited a fibrous microstructure, surface area was 138. 9 m^2/g and average pore diameter was about 15 nm. V2O5 aerogels were crystalline when annealed at 300℃. The electrochemical impedance spectra （EIS） with different potentials were studied by fitting EIS date to an equivalent circuit, and then some kinetics parameters were analyzed and discussed. The electrochemical measurements have shown that the specific capacity of V205 aerogels derived by the ambient pressure dry is 300.45mAh/g, and it can be used as a good cathode material for Lithium batteries.