The scalability of Microbial fuel cells (MFCs) is key to the development of stacks. A recent study has shown that self-stratifying membraneless MFCs (S-MFCs)could be scaled down to 2 cm without performance deterioration. However, the scaling-up limit of S-MFC is yet unknown. Here the study evaluates the scale-up height of S-MFCs treating urine, from 2cm, 4cm to 12cm high electrodes. The electrochemical properties of the S-MFCs were investigated after steady-states were established, following a 70-days longevity study. The electrochemical properties of the 2 cm and 4 cm conditions were similar (5.45±0.32 mW per cascade). Conversely, the 12 cm conditions had much lower power output (1.48±0.15 mW). The biofilm on the 12 cm cathodes only developed on the upper 5-6 cm of the immersed part of the electrode suggesting that the cathodic reactions were the limiting factor. This hypothesis was confirmed by the cathode polarisations showing that the 12 cm S-MFC had low current density (1.64±9.53 µA.cm^-2, at 0 mV) compared to the other two conditions taht had similar current densities (192.73±20.35 µA.cm^-2, at 0 mV). These results indicate that S-MFC treating urine can only be scaled-up to an electrode height of around 5-6 cm before the performance is negatively affected.

微生物燃料电池（MFC）的可扩展性是电池组开发的关键。最近的研究表明，自分层无膜MFC（S-MFC）可以缩小到2 cm，而不会降低性能。但是，S-MFC的放大极限仍然未知。在这里，研究评估了S-MFCs处理尿液的放大高度，电极高2cm，4cm至12cm。经过长达70天的寿命研究，在建立稳态之后，对S-MFC的电化学性能进行了研究。2 cm和4 cm条件下的电化学性质相似（每个级联为5.45±0.32 mW）。相反，在12 cm的条件下功率输出要低得多（1.48±0.15 mW）。12 cm阴极上的生物膜仅在电极浸入部分的上部5-6 cm处显影，这表明阴极反应是限制因素。阴极极化证实了这一假设，表明12 cm S-MFC具有低电流密度（1.64±9.53 µA.cm^-2，在0 mV时）与其他两个条件相比，具有相似的电流密度（192.73±20.35 µA.cm ^-2，在0 mV时）。这些结果表明，在对性能产生负面影响之前，用S-MFC处理尿液只能扩大到5-6 cm左右的电极高度。