Artist’s interpretation of the new riboflavin and glucose flow battery. Credit: Nathan Johnson, Adapted from ACS Energy Letters 2025, DOI 0.1021acsenergylett.5c02462
Chemists have designed a new kind of flow battery that takes inspiration from biological systems to produce energy from glucose (sugar) with the help of a riboflavin (vitamin B2) catalyst.
“Riboflavin and glucose flow cells can generate electricity from naturally derived energy sources,” says the study’s lead author, Jong-Hwa Shon, from Pacific Northwest National Laboratory, USA.
Glucose can be sourced sustainably and at low cost from biomass or chemical production, which the authors say makes it “an appealing choice as an active material for long-duration energy storage”.
“Using non-toxic components that are both inexpensive and naturally abundant, this system offers a promising pathway toward safer and more affordable residential energy storage,” says Shon.
Flow batteries use 2 liquid electrolytes, a catholyte and anolyte, which flow across the positive and negative electrodes (cathode and anode) and undergo reduction-oxidation reactions to generate a flow of electricity.
The team constructed the electrodes from carbon. The anolyte flowing around the anode contained glucose and an active form of riboflavin, which replaced expensive noble metals that would traditionally be used as the catalyst.
A basic (alkaline) solution of potassium ferricyanide, which allowed the team to precisely measure riboflavin’s catalytic activity, served as the catholyte in one demonstration. Oxygen gas, which is a more cost-effective option for large-scale, practical use, was used in another.
The glucose-O2 fuel cell achieved a peak power density of 13 milliwatts per cm2, which according to the researchers is 20 times greater than the previously reported value from a glucose flow battery under similar conditions.
However, the flow battery containing oxygen had slower reactions at the electrodes than the potassium ferricyanide design.
The researchers say this is likely due to oxygen breaking down riboflavin in the presence of light. They plan to improve the power density of the cell by preventing these reactions and improving its engineering.
The findings are reported in ACS Energy Letters.