Self-stratified and self-powered micro-supercapacitor integrated into a microbial fuel cell operating in human urine

Santoro, Carlo; Walter, Xavier Alexis; Soavi, Francesca; Greenman, John; Ieropoulos, Ioannis

Abstract

© 2019 The Authors 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%.

• Journal Article Type: Article
• Acceptance Date: Mar 27, 2019
• Online Publication Date: Mar 29, 2019
• Publication Date: Jun 1, 2019
• Deposit Date: Apr 17, 2019
• Publicly Available Date: Apr 17, 2019
• Journal: Electrochimica Acta
• Print ISSN: 0013-4686
• Publisher: Elsevier
• Peer Reviewed: Peer Reviewed
• Volume: 307
• Pages: 241-252
• DOI: https://doi.org/10.1016/j.electacta.2019.03.194
• Keywords: microbial fuel cell, supercapacitor, high power density, urine, discharge, self-powered
• Public URL: https://uwe-repository.worktribe.com/output/846247
• Publisher URL: https://doi.org/10.1016/j.electacta.2019.03.194
• Contract Date: Apr 17, 2019