近年来,随着柔性电子的快速发展,制造柔性、微型、大面积和低成本的储能器件得到了极大的关注。以六水硝酸镍/钴为原料、硫脲为硫化剂、引入热解g-CN,通过一步溶剂热制备NiCo_(2)S_(4)/g-CN纳米复合材料。采用掩膜版将调配的NiCo_(2)S_(4)/g-CN油墨印刷在柔性聚对苯二甲酸乙二醇酯基底形成叉指结构电极,继而涂覆凝胶电解质组装成柔性叉指型超级电容器。结构和电化学性能研究表明:NiCo_(2)S_(4)纳米晶分布生长在g-CN纳米片层表面,引入的g-CN起到增强NiCo_(2)S_(4)充放电过程中的电荷传输及容纳其体积膨胀的作用,复合材料电极在10 m A/cm^(2)的电流密度下面积比电容为9.1 F/cm^(2)。组装的叉指电容器可在–0.2~0.6 V的电压下工作,并且在高至500 m V/s的扫描速率下保持稳定,表明器件良好的倍率性能。在20 m V/s的扫描速率下,器件的面积比电容可达5.7 m F/cm^(2),当功率密度为17.5 m W/cm~3时,器件的能量密度为0.56 m W·h/cm^(3)。
A New Niobate Ba 5LaTi 2Nb 3O 18 was synthesized by a high temperature solid state reaction in the BaO-La 2O 3-TiO 2-Nb 2O 5 system. The chemical compositions, crystal structure, microstructure, density and melting point of the new compound were characterized by EPMA, XRD, SEM, DTA and so on. Ba 5LaTi 2Nb 3O 18 crystallizes the rhombohedral system with unit cell parameters a=0 573 25(2) nm, c=4 213 9(2) nm, and space group R3m, Z=3. The structure may be described as five (Nb,Ti)O 6 octahedra corner-sharing along c axis to form perovskite layer connected by Ba atoms. The Ba 5LaTi 2Nb 3O 18 ceramic exhibits a high dielectric constant of 80.5, low dielectric loss of 6.5×10 -4 and small temperature coefficient of dielectric constant of -78×10 -6 K -1 at 1 MHz due to its close structure and relative high dielectric polarizabilities of Ba 2+, La 3+, Ti 4+ and Nb 5+. Ba 5LaTi 2Nb 3O 18 might be a suitable candidate of high ε r microwave dielectric ceramics.
