A hybrid battery technology engineered in China not only stores and delivers electricity but also produces biomass-derived chemicals in a flow system. The furfural–nickel hydroxide battery converts furfural sourced from agricultural biomass into either furfuryl alcohol or furoic acid.

The module architecture combines rechargeable with redox flow battery concepts to realize both electricity storage and chemical production functions. Inclusion of a rhodium-copper based bifunctional metal catalyst for the anode supports conversion of electrolyte-containing furfural into furfuryl alcohol when the battery is charged; furoic acid is formed as the battery is discharged. The cathode is assembled with a cobalt-doped nickel hydroxide material, similar to that used in traditional nickel–zinc or nickel–metal hydride batteries.

After charging with a solar cell, four series-connected hybrid batteries designed by researchers from Tsinghua University and Beijing University of Chemical Technology were demonstrated to power LED lights, smart phones and other devices while continually producing furfuryl alcohol and furoic acid during battery cycling. The chemicals are conducted away using a flow system.

The system described in Angewandte Chemie International Edition offers a peak power density up to 107 mW/cm² in addition to the production of value-added chemicals of use as precursors in the manufacture of resins, flavors and pharmaceuticals.