For every pint of beer produced by a brewery, seven pints of waste water are created. And it can't just be washed down the drain—the waste requires extra cleaning first. But what if the gunk that comes out of that water could be used for something useful? Like, for making batteries? That's exactly what a research team at University of Colorado Boulder is doing.
The process is simple in principal: Take brewery waste and use it to grow fibrous, mushroomy fungus, resulting in a "mycelia mat." Then heat that mat to extreme temperatures, as if making charcoal. The resulting material can be used directly one of the electrodes in a lithium-ion battery, the kind of battery used by your smartphone or laptop.
Did you ever wonder why burnt toast can blow up your toaster? It's because the carbon produced by burning toast is conductive, and it shorts out the electrical heating elements. Biomass is often used to make the carbon-based electrodes needed in batteries, and these days we need a lot of batteries. The problem is that, usually, this biomass can be in short supply or requires a lot of work to extract and then to get into the right form for processing.
Fungus grown in beer waste, however, turns out to be perfect. Not only is the sugary runoff cheap and plentiful, it also allows the researchers to more easily fine-tune the resulting fungus.
"The novelty of our process is changing the manufacturing process from top-down to bottom-up, CU Boulder associate professor Zhiyong Jason Ren told the university newsroom. "We’re bio-designing the materials right from the start."
The result is in "one of the most efficient naturally derived lithium-ion battery electrodes known to date." The process creates such great electrodes that the cleaning up of the brewery waste is almost just a side effect.
The team has patented its process, which is a first step to a commercial exploitation that will help two industries at the same time. The process is also easily scalable, because there is no shortage of the raw material. So, while you won't have a battery made from actual beer in your cell phone, this is the next best thing. Better, in fact, because every pint used in a beer battery would be a pint that couldn't be drunk.