电解-电化学混合电容器的制备与性能

为解决电化学电容器工作电压过低的问题, 本文以钽电解电容器的烧结型钽块为阳极, 聚苯胺(PANI)/TiO₂电化学电容器复合电极为阴极, 成功制备了高能量密度、高工作电压的电解-电化学混合电容器. PANI/TiO₂复合电极是通过在多孔阳极氧化钛纳米管阵列中电化学聚合PANI 制得. 该阴极具有优良的倍率特性, 当平均功率密度为0.55 mW·cm^-2时, 对应的比容量仍达到10.0 mF·cm^-2. 由于与电解电容器复合, 该混合电容器的单元工作电压可高达100 V. 而且电化学电容器阴极的比容量远大于阳极, 故阴极所需尺寸远小于阳极, 节省的空间可用于增大阳极尺寸, 从而使混合电容器的比容量极大提高. 所制备的混合电容器体积能量密度和质量能量密度分别是钽电解电容器的4 倍和3 倍. 将该混合电容器在100 V下进行短路充放电实验, 循环10000 次后发现容量未衰减, 等效串联电阻未增加, 显示出极好的循环稳定性和功率特性. 计算表明其最大功率密度高达847.5 W·g^-1. 电化学阻抗谱显示其具有优良的阻抗特性和频率特性.

Fabrication and Performance of Electrolytic-Electrochemical Hybrid Capacitors

To solve the issue of comparatively low operation voltage of electrochemical capacitors, a hybrid capacitor consisting of the anode electrode of tantalum electrolytic capacitor and the cathode electrode of polyaniline (PANI)/TiO₂ with high energy density and high working voltage was developed. The PANI/TiO₂ composite electrode for use as the capacitor cathode was prepared by in situ electrochemical polymerization of aniline in porous anodic titania nanotube arrays on titanium foil substrates. The composite electrode showed good rate capability with a specific capacitance of 10.0 mF·cm^-2 and a high power density of 0.55 mW·cm^-2. Using a dielectric coated anode electrode, the single-cell hybrid capacitor could withstand working voltages as high as 100 V. As the PANI/TiO₂ composite cathode only requires a small volume because of its high specific capacitance, available space can be used to enlarge the anode electrode, leading to an increase in specific capacitance of the hybrid capacitor. The hybrid capacitor had high volumetric and gravimetric energy densities, which were about four times and three times higher than those of a tantalum electrolytic capacitor. The short circuit charge-discharge cycle test for the hybrid capacitor at 100 V showed that its capacitance did not decrease, and the equivalent series resistance did not increase after 10000 cycles, indicating excellent cycle stability and power performance. The peak power density was estimated to be 847.5 W·g^-1. In addition, electrochemical impedance spectroscopy data indicated that the hybrid capacitor had good impedance and frequency characteristics.