Uncertainties of Yeast‐Based Biofuel Cell Operational Characteristics

Abstract

The commonly used parameters characterizing fuel cells and in particular microbial fuel cells (MFCs) electrical performance are open circuit voltage (OCV), maximum power, and short circuit current. These characteristics are usually obtained from polarization and power curves. In the present study, the expanded uncertainties of operational characteristics for yeast‐based fuel cell were evaluated and the main sources of uncertainty were determined. Two approaches were used: the uncertainty budget building for sources uncertainty estimation and a statistical treatment of identical MFCs results – for operational characteristics uncertainty calculation. It was found that in this particular bioelectrochemical system the major factor contributing to operational characteristics uncertainties was the electrodes' resistance. The operational characteristics uncertainties were decreased from 19 to 13% for OCV, from 42 to 14% for maximal power, and from 46 to 13% for short circuit current with the usage of electrodes with resistance in the interval 6–7 Ω. The described approaches can be used for operational characteristics expanded uncertainties calculation of all types of fuel cells using data from polarization measurements.

Catalytic biofilm formation by Shewanella oneidensis MR-1 and anode characterization by expanded uncertainty

“…Three symbols are used to express uncertainty [18]. Measurement or Standard uncertainty (u), which expresses the concept as a standard deviation.…”

“…As an estimation of the measured value, the median of all replicates is applied. The uncertainty is related to the median of absolute deviations (MAD) and normalized median of absolute deviation (MADN), which becomes compatible with the standard deviation [18,22]. When polarization curves are measured, the generated current is established.…”

Untitled

“…This approach is highly innovative in this field and it relies on statistical analysis and data interpretation. Through evaluation of the expanded uncertainty of microbial fuel cells, the variations in electrodes resistance and mostly difference in their electrochemical accessible surface area were identified as the main parameters causing irreproducibility of MFCs responses [24,25]. The idea of using statistical approaches for analysis of biofuel cells was further enlarged to include Design of Experiments, Principal Component Analysis (PCA) and Canonical Correspondence Analysis [7,[26][27][28][29].…”

“…Expanded uncertainty is a new term in the field of biofuel cells, which was recognized as necessary and introduced for the interpretation of results first from microbial fuel cells [24,25]. As for conventional fuel cells, the commonly used electrochemical techniques for MFCs operational characteristics determination are polarization and power curves.…”

Bioelectrocatalysis and More

“…Thus, uncertainty estimation of operational characteristics is required by the contemporary regulations for proper result presentation and comparison between results obtained in different laboratories under different experimental conditions. Study of the contributions of various uncertainty sources to the combined uncertainty allows to perform optimization of the experimental parameters having highest contribution to the uncertainty and, thus to obtain more reliable electrochemical system with reproducible output values [25]. This is a question of crucial importance for the future practical application of biofuel cells especially when biosensors are developed.…”