Faster Time Response by the Use of Wire Electrodes in Capacitive Salinity Gradient Energy Systems
Faster Time Response by the Use of Wire Electrodes in Capacitive Salinity Gradient Energy Systems
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DOI：
10.1021/jp306522g
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发表时间：
2012-09-13
影响因子：
3.7
通讯作者：
Hamelers, Hubertus V. M.
中科院分区：
文献类型：
--
作者：
Burheim, Odne S.;Liu, Fei;Hamelers, Hubertus V. M.
基于Donnan势的电容能量提取（CDP）和基于双电层膨胀的电容能量提取（CDLE）是将海水和河水混合物的势能自由能转化为电能的新型电化学过程。这通过使用具有和不具有离子交换膜的超级电容器电极来完成。目前，这些技术依赖于改进的质量传输，以便变得更有效并提供更高的功率输出。在本文中，我们评估的传输现象扩散和电极的几何形状时，在开路电位（OCP）的海水和河水之间切换。通过改变电极的几何形状从平板到圆柱形的，实验和分析模型相结合表明，通过扩散的传质增加。这在流体动力学条件没有任何变化的情况下得到证明。在不改变水动力条件的情况下改善质量输送打破了科学界关于盐度梯度动力的惯例。此外，在海水中的传输现象似乎是由扩散控制的，并且当使用线电极代替平板电极时，在这种条件下在CDP和CDLE中建立开路电位的响应时间减少了2倍。在河水中，趋势相似，但响应时间通常较长。
Capacitive energy extraction based on Donnan potential (CDP) and capacitive energy extraction based on double layer expansion (CDLE) are novel electroctrochemical processes to convert the potential free energy of mixing sea and river water into electric work. This is done by the use of supercapacitor electrodes with and without ion exchange membranes. Currently, these techniques rely on improved mass transport in order to become more efficient and give higher power output. In this paper we evaluate the transport phenomena by diffusion and the electrode geometry when switching between sea and river water at open circuit potential (OCP). By changing the electrode geometry from a flat plate to a cylindrical one, experiments and analytical models in combination show that mass transport by diffusion is increased. This is demonstrated without any changes in the hydrodynamic conditions. Improving mass transport without changing the hydrodynamic conditions breaks with what has been the convention in the scientific community of salinity gradient power. Moreover, in sea water the transport phenomena appear to be controlled by diffusion, and the response time for building open circuit potential in CDP and CDLE under this condition is reduced by a factor of 2 when using wire electrodes instead of flat plate electrodes. In river water, the trend is similar though the response time is generally larger.