超级电容器能量密度的提升策略

超级电容器最大的优点是具有优良的脉冲充放电性能和快速充放电性能，同时具有循环寿命长、工作温度范围宽、安全无污染等特性，但能量密度较低. 本文对超级电容器的工作原理、发展状况、缺陷所在和改进方法进行了简要介绍，以本课题组在高比能超级电容器方面的研究工作为主线，结合近几年的文献报道，重点阐述了超级电容器能量密度的提升策略. 主要围绕以下三个方面开展了工作：1）通过将电极材料尺寸纳米化来提高传统电极材料的比容量或开发其他高比容量的电极材料；2）发展具有高电压窗口的离子液体电解液，或利用不同材料在不同电位区间的电容特性构筑不对称电容器，从而提高超级电容器的电压窗口；3）将超级电容器和锂离子电池进行“内部交叉”构筑兼具高能量密度和高功率密度的锂离子混合电容器. 最后，对超级电容器的发展进行了展望.

Strategies to Enhance Energy Density for Supercapacitors

The biggest advantage of supercapacitor lies in not only the excellent pulse and fast charging-discharging performance, but also the characteristics of long cycle life and wide operating temperature window with no pollution. However, the energy density of supercapacitor is low. In this paper, the working principle, the development status, defects and improvement method of supercapacitors are introduced. Based on the research workes of the supercapacitors with high energy density in our group, combined with the literature reports in recent years, the strategies to promote the energy density of supercarpacitors will be focused. The strategies for the enhancement of energy density include: 1) to increase the specific capacitance of the electrode by reducing the existing materials to nano sizes or to develop new materials with high capacity; 2) to increase the voltage window of the supercapacitor by developing ionic liquid electrolyte with high voltage window or to adopt asymmetric supercapacitors in which one electrode is pseudocapacitive, while the other utilizes double layer capacitance; 3) to build lithium ion hybrid supercapacitors with both high energy density and high power density by “internal cross” the supercapacitor and lithium ion battery. Finally, the prospects in the future development of supercapacitors will be provided.