Lim Keng Guan, Palmore G Tayhas R
Division of Engineering, Brown University, Providence, RI 02912, USA.
Biosens Bioelectron. 2007 Jan 15;22(6):941-7. doi: 10.1016/j.bios.2006.04.019. Epub 2006 Jun 5.
Microfluidic biofuel cells exploit the lack of convective mixing at low Reynolds number to eliminate the need for a physical membrane to separate fuel from oxidant. This paper demonstrates how the length and spacing of electrodes within a microchannel, and thus thickness of the diffusion layer, affects the performance of a microfluidic biofuel cell. It was found that splitting a single electrode into two (or more) smaller electrodes and separating them by a distance equal to three times their length prevents the continuous increase in thickness of a diffusion layer. This change results in a 25% increase in maximum power density compared to a single electrode device with identical electroactive area. Furthermore, we found that the maximum current density of a microfluidic biofuel cell operated with different electrode configurations (i.e., length of cathode) closely matches that predicted by theory.
微流控生物燃料电池利用低雷诺数下缺乏对流混合的特点，从而无需使用物理膜来分离燃料和氧化剂。本文展示了微通道内电极的长度和间距，进而扩散层的厚度，如何影响微流控生物燃料电池的性能。研究发现，将单个电极拆分为两个（或更多）较小的电极，并将它们隔开三倍于其长度的距离，可防止扩散层厚度持续增加。与具有相同电活性面积的单电极装置相比，这一变化使最大功率密度提高了25%。此外，我们发现，采用不同电极配置（即阴极长度）运行的微流控生物燃料电池的最大电流密度与理论预测值紧密匹配。
