Knowledge of the performance of microbial electrolysis cells under a wide range of operating conditions is crucial to achieve high production efficiencies. Characterizing this performance in an experiment, however, is challenging due to either the long measurement times of steady-state procedures or the transient errors of dynamic procedures. Moreover, wide parallelization of the measurements is not feasible due to the high measurement equipment cost per channel. Hence, to speedup this characterization and to facilitate low-cost, yet widely parallel measurements, this paper presents a novel rapid polarization curve measurement procedure with a dynamic measurement resolution that runs on a custom six-channel potentiostat with a current-driven topology. As case study, the procedure is used to rapidly assess the impact of altering pH values on a microbial electrolysis cell that produces H 2 . A ×2-×12 speedup could be obtained in comparison with the state-of-the-art, depending on the characterization resolution (16-128 levels). On top of this speedup, measurements can be parallelized up to 6× on the presented, affordable-42$-per-channel-potentiostat.

A 128-channel potentiostat for high-throughput microbial electrochemistry • Accompanying 128 gold electrode array (77 functional electrodes) • Anodic electroactive biofilms simultaneously grown at 11 electrode potentials (n = 7) • Midpoint potentials and charge transport parameters assessed by cyclic voltammetry • Most performant EABs grown just below anodic plateau (−0.3 V and −0.25 V vs. Ag/AgCl) A chip-based 128-channel potentiostat for high-throughput studies of bioelectrochemical systems: optimal electrode potentials for anodic biofilms

Electrochemical monitoring is crucial for both industrial applications, such as microbial electrolysis and corrosion monitoring as well as consumer applications such as personal health monitoring. Yet, state-of-the-art integrated potentiostat monitoring devices have few parallel channels with limited flexibility due to their channel architecture. This work presents a novel, widely scalable channel architecture using a switch capacitor based Howland current pump and a digital potential controller. An integrated, 64-channel CMOS potentiostat array has been fabricated. Each individual channel has a dynamic current range of 120dB with 1.1pA precision with up to 100kHz bandwidth. The on-chip working electrodes are post-processed with gold to ensure (bio)electrochemical compatibility.

Bio)electrochemical reactions are a promising, environmentally friendly alternative for many chemical processes. These processes, however, are known to be slow in time, to be strongly dependent on the environment and to vary between different samples. This necessitates research on studying optimal operating conditions of the (bio)electrochemical cells. Yet, current experiments have to rely on slow, sequential tests. To overcome these, this work proposes a potentiostat with 128 parallel channels to speed up research experiments. The 128-channel potentiostat makes extensive use of time-sharing and is implemented with PCB technology resulting in a cost-per-channel of only 5$, 4x lower than the state-of-the-art (SotA) and an area-per-channel of ≈ 93 mm 2 , 5x lower than the SotA. Realtime digital compensation of each individual channel is used to obtain a channel-to-channel mismatch below 1%. A cyclic voltametry experiment on all channels simultaneously illustrates the low channel-to-channel mismatch. A chronoamperometry experiment with 128 different potential steps in parallel illustrates the 128x experiment speedup.