Diversifying Biological Fuel Cell Designs by Use of Nanoporous Filters

Authors

Justin C. Biffinger, US Naval Research LaboratoryFollow
Ricky Ray, Naval Research Laboratory
Brenda Little, Naval Research LaboratoryFollow
Bradley R. Ringeisen, Naval Research LaboratoryFollow

Date of this Version

2007

Comments

Published in Environ. Sci. Technol. (2007) 41, 1444-1449; doi: 10.1021/es061634u

Abstract

The use of proton exchange membranes (PEMs) in biological fuel cells limits the diversity of novel designs for increasing output power or enabling autonomous function in unique environments. Here we show that selected nanoporous polymer filters (nylon, cellulose, or polycarbonate) can be used effectively in place of PEMs in a miniature microbial fuel cell (mini-MFC, device cross-section 2 cm²), generating a power density of 16 W/m³ with an uncoated graphite felt oxygen reduction reaction (ORR) cathode. The incorporation of polycarbonate or nylon membranes into biological fuel cell designs produced comparable power and durability to Nafion-117 membranes. Also, high power densities for novel larger (5 cm³ anode volume, 0.6 W/m³) and smaller (0.025 cm³ projected geometric volume, average power density 10 W/m³) chamberless and pumpless microbial fuel cells were observed. As an additional benefit, the nanoporous membranes isolated the anode from invading natural bacteria, increasing the potential applications for MFCs beyond aquatic sediment environments. This work is a practical solution for decreasing the cost of biological fuel cells while incorporating new features for powering long-term autonomous devices.