不同介孔结构的磷酸钛的制备及性能

Abstract

采用溶胶凝胶模板法结合煅烧的方法,通过选用不同的模板剂合成得到具有不同介孔结构的磷酸钛材料,运用X-射线粉末晶体衍射技术(Xrd)、低温n2吸脱附技术和高分辨透射电子显微技术(HrTEM)对样品进行了表征,并分别对各材料的介孔结构及其电化学性能进行了研究。结果表明,材料介孔结构的长程有序性及其孔径大小都对材料的电化学性能有影响,例如在大电流密度下(如:150MA/g),长程有序性较好的与长程有序性较差的磷酸钛介孔材料的首次放电比容量分别为93.9、67.9MA/g,经过100次循环后,容量的保持率分别为54%、20%;大孔径与小孔径的磷酸钛介孔材料的首次放电比容量分别为96.1、67.9MA/g,经过50次循环后,容量的保持率分别为66%、17%。

Titanium phosphate materials with different mesoporous structure were prepared by sol-gel different templates combined with calcination method.The mesoporous structure of the materials was characterized by small angle X-ray diffraction (SA-XRD) method, N2 adsorption/desorption techniques, and high resolution transmission electron microscopy (HRTEM).The results show that both the length of ordered mesostructure and pore size has a great influence on the electrochemical performance of the titanium phosphate materials.For example, the titanium phosphate materials with ordered and worse structure respectively delivers an initial discharge capacity of about 93.9 mA/g and 67.9 mA/g at 150 mA/g, and after 100 cycles, the capacity retention is 54% and 20% respectively.However, the titanium phosphate materials with the large and small pore size respectively delivers the initial discharge capacity of about 96.1 mA/g and 67.9 mA/g, and after 50 cycles, the capacity retention was 66% and 17% respectively.