Bristol Robotics Laboratory, University of the West of England, Bristol Business Park, Coldharbour Lane, Bristol BS16 1QD, United Kingdom.
Bioelectrochemistry. 2011 Apr;81(1):22-7. doi: 10.1016/j.bioelechem.2011.01.001. Epub 2011 Jan 14.
A method for assessing the performance of microbial fuel cells (MFCs) is the polarisation sweep where different external resistances are applied at set intervals (sample rates). The resulting power curves often exhibit an overshoot where both power and current decrease concomitantly. To investigate these phenomena, small-scale (1 mL volume) MFCs operated in continuous flow were subjected to polarisation sweeps under various conditions. At shorter sample rates the overshoot was more exaggerated and power generation was overestimated; sampling at 30 s produced 23% higher maximum power than at 3 min. MFCs with an immature anodic biofilm (5 days) exhibited a double overshoot effect, which disappeared after a sufficient adjustment period (5 weeks). Mature MFCs were subject to overshoot when the anode was fed weak (1 mM acetate) feedstock with low conductivity (<100 μS) but not when fed with a higher concentration (20 mM acetate) feedstock with high conductivity (>1500 μS). MFCs developed in a pH neutral environment produced overshoot after the anode had been exposed to acidic (pH 3) conditions for 24 h. In contrast, changes to the cathode both in terms of pH and varying catholyte conductivity, although affecting power output did not result in overshoot suggesting that this is an anodic phenomenon.
评估微生物燃料电池 (MFC) 性能的一种方法是极化扫描，其中在设定的间隔（采样率）施加不同的外部电阻。由此产生的功率曲线通常会出现过冲现象，即功率和电流同时下降。为了研究这些现象，在连续流动条件下，采用小型（1 mL 体积）MFC 进行了极化扫描。在较短的采样率下，过冲现象更加明显，发电被高估；以 30 s 的采样间隔产生的最大功率比 3 min 时高出 23%。阳极生物膜不成熟（5 天）的 MFC 表现出双重过冲效应，在经过足够的调整期（5 周）后消失。当阳极进料为低电导率（<100 μS）的弱（1 mM 乙酸盐）进料源时，成熟的 MFC 会出现过冲，但当进料源为高电导率（>1500 μS）的高浓度（20 mM 乙酸盐）进料源时则不会出现过冲。在阳极暴露于酸性（pH 3）条件 24 h 后，在中性 pH 环境中开发的 MFC 也会出现过冲现象。相比之下，尽管阴极的 pH 和阴极电解液电导率的变化会影响功率输出，但不会导致过冲，这表明这是一种阳极现象。
