Self-stratified and self-powered micro-supercapacitor integrated into a microbial fuel cell operating in human urine. (1st June 2019)

• Record Type: Journal Article
• Authors: Santoro, Carlo; Walter, Xavier Alexis; Soavi, Francesca; Greenman, John; Ieropoulos, Ioannis
• Is Part Of: Electrochimica acta. Volume 307(2019)
• Page Start: 241
• Page End: 252
• Publication Date: 2019-06-01
• Subjects: Microbial fuel cell -- Supercapacitor -- High power density -- Urine -- Discharge -- Self-powered; Electrochemistry -- Periodicals; Electrochemistry, Industrial -- Periodicals; 541.37
• DOI: 10.1016/j.electacta.2019.03.194
• Languages: English
• ISSNs: 0013-4686

Abstract

Abstract: A self-stratified microbial fuel cell fed with human urine with a total internal volume of 0.55 ml was investigated as an internal supercapacitor, for the first time. The internal self-stratification allowed the development of two zones within the cell volume. The oxidation reaction occurred on the bottom electrode (anode) and the reduction reaction on the top electrode (cathode). The electrodes were discharged galvanostatically at different currents and the two electrodes were able to recover their initial voltage value due to their red-ox reactions. Anode and cathode apparent capacitance was increased after introducing high surface area activated carbon embedded within the electrodes. Peak power produced was 1.20 ± 0.04 mW (2.19 ± 0.06 mW ml −1 ) for a pulse time of 0.01 s that decreased to 0.65 ± 0.02 mW (1.18 ± 0.04 mW ml −1 ) for longer pulse periods (5 s). Durability tests were conducted over 44 h with ≈2600 discharge/recharge cycles. In this relatively long-term test, the equivalent series resistance increased only by 10% and the apparent capacitance decreased by 18%. Graphical abstract: Image 1 Highlights: Supercapacitive microbial fuel cells fed with human urine were investigated. Galvanostatic discharges were studied and key parameters presented. ESR and capacitance were improved by adding supercapacitive features. Highest power obtained was 1.20 ± 0.04 mW (2.19 ± 0.06 mW ml −1 ) for a tpulse of 0.01 s. Stability over 2600 cycles of discharge/self-recharge (44 h) was shown.