High performance direct liquid fuel cells powered by xylose or glucose

Abstract

In this work, we report the first abiotic, direct liquid fuel cells powered by the monosaccharide xylose using both a fully alkaline fuel cell (with anion exchange membrane) and a split pH fuel cell (with cation exchange membrane). We also report that the same fuel cells can be used with the monosaccharide glucose to produce much higher maximum power density than previously reported for abiotic, direct glucose fuel cells. This first alkaline direct xylose fuel cell (DXFC) produces a maximum power density of 57 mW cm−2 at optimum conditions, while the split pH DXFC produces a maximum power density of 160 mW cm−2. Our significantly improved alkaline direct glucose fuel cell (DGFC) produces 90 mW cm−2 at optimum conditions, while the split pH DGFC produces 189 mW cm−2. In addition to being high performing, these sugar molecules are naturally abundant, renewable, and known to convert to valuable products such as gluconic acid, glucaric acid, and xylonic acid during electrochemical oxidation. Other fuel cell and electrochemical cell data is also reported herein to understand the role of pH and fuel concentrations on behavior toward the electrochemical oxidation of these sugar molecules in alkaline media.