Examining supercapacitor characteristics in order to extend supercapacitor life

对替代能源/存储系统的追求从未像现在这样激烈，储能市场的一个强有力的竞争者是超级电容器，它类似于电池，但像电容器一样存储电荷（其中有两个金属板，正电荷存储在一个板上，而负电荷存储在另一个板上）。然而，与典型的电容器不同，超级电容器能够在相同的几何面积上存储大约一百万倍的电荷。最近，人们对超级电容器在车辆应用（用于冷启动辅助和混合燃料电池电容器汽车负载均衡）、电力线备用和用于间歇性电源的能量存储（即，太阳能电池板或风车涡轮机）。然而，限制其实际应用的超级电容器行为的一个非常不为人知的方面是自放电（SD）现象，即超级电容器在长时间充电时表现出的自发电压损失。显然，这具有实际重要性，因为人们想知道超级电容器是否准备好使用，无论它是否已经使用了一天或一年。 本研究旨在发现并克服超级电容器SD的原因，并研究改变这种放电速率的因素。为了检查SD过程，超级电容器将在SD之前和之后使用电化学（用电来检查系统的特性）进行检查。这些实验将使我们能够检查SD对超级电容器的电荷和能量存储能力的影响。传统上，各种物质已被用作超级电容器电极，包括碳、电子导电聚合物、IrO 2、RuO 2和MnO 2。这项工作最初将集中在高表面积，稳定的碳电极，但将扩大到包括传统和新型超级电容器材料。通过更全面地了解自放电过程，希望可以最大限度地减少甚至完全防止自放电，从而延长超级电容器的寿命。

The quest for alternative energy sources / storage systems has never been more intense than it is at present, and one strong contender for the energy storage market is the supercapacitor, which is similar to a battery, but stores charge like a capacitor (where there are two metal plates and positive charges are stored on one plate while negative charges are stored on the other). Unlike typical capacitors, however, supercapacitors are able to store approximately a million times more charge on the same geometric area. There has been significant recent interest in the use of supercapacitors in vehicle applications (for cold starting assistance and hybrid fuel-cell capacitor car load levelling), power line backup, and energy storage for intermittent power sources (i.e., solar panels or windmill turbines). However, one very poorly understood aspect of supercapacitor behaviour which limits their practical application is the phenomenon of self-discharge (SD), the spontaneous loss of voltage exhibited by a supercapacitor as it sits charged for long periods of time. Obviously, this is of practical importance as one would like to know that the supercapacitor is ready for use, whether it has been unused for a day or a year.      This research is designed to discover, and later overcome the causes of supercapacitor SD and study the factors which change the rate of this discharge. In order to examine the SD processes, the supercapacitor will be examined before and after SD using electrochemistry (using electricity to examine a system's characteristics). These experiments will allow us to examine the effect of SD on the charge and energy storage capability of the supercapacitor. Traditionally, a variety of species have been used as supercapacitor electrodes, including carbon, electronically conducting polymers, IrO2, RuO2 and MnO2. This work will initially focus on high surface area, stable carbon electrodes, but will expand to encompass both traditional and novel supercapacitor materials. By gaining a more complete understanding of the self-discharge process it is hoped that it can be minimized or even prevented altogether, thereby extending the life of the supercapacitor.