Rhubarb battery, anyone?
A group at Harvard University has created an aqueous flow battery that uses a quinone, a type of organic molecule that happens to have favorable electrochemical properties. The particular quinone they used is nearly identical to one found in rhubarb.
Flow batteries, which date back more than three decades, replace the solid electrodes of standard batteries with two liquid electrolytes. The liquids, contained in separated tanks, flow through a cell stack, letting ions and electrons move through a porous membrane in order to discharge and recharge the battery. They are considered good candidates for large-scale renewable energy storage because you can scale up the tank size of a flow battery in order to increase the megawatt-hours of storage available without being forced to also scale up the power capacity; with more traditional batteries like lithium-ion, the components come as a package deal, meaning to achieve 50 megawatt-hours of energy storage you also need to pay for 50 megawatts capacity.