If it wasn’t for one, niggling, deal-breaking factor — reliability — alternative, renewable energy sources would probably overtake fossil fuels in terms of commercial viability and desirability. Wind and solar power plants are awesome, cost-effective, infinite-until-the-Sun-burns-out solutions — but when the sun goes in, or the wind dies down, you need a backup power source. Today, that’s fossil and nuclear power — but thanks to a discovery made by Stanford University researchers, we might soon be able to use batteries.

Now, batteries are already extensively used in the power grid to even out the peaks and troughs of generation and consumption — but such batteries are incredibly expensive, must be regularly maintained, and have very short lifespans. Stanford, however, has developed a new battery electrode that can survive 40,000 charge/discharge cycles — enough for 30 years of use on the grid. Its ruggedness and longevity is a virtue of the material being used: copper hexacyanoferrate. This copper compound has a crystalline structure (pictured below right) that very readily allows charge-carrying ions to move in and out of the electrode. Further improving its performance, the copper compound is used in tiny, nanoparticle clumps of just 100 atoms. Much like the way that hole-punched graphene improves lithium-ion batteries, nanoparticles of the copper crystal mean that charge ions have less distance to travel.

When all said and done, the end result is a cathode that’s capable of charging very rapidly and discharging very high voltages — exactly what the alternative energy grid needs. The only problem is, a high-voltage cathode (-) requires a very low-voltage anode (+) — and the Stanford researchers haven’t found the right one yet; and so they haven’t actually made a battery with this new discovery. It’s an awesome battery in potentia. Stanford’s lead materials science engineer, Yi Cui, (who is a bit of a battery whizz), says they have some promising candidates for the anode, though.

Finally, this new nanoparticle cathode is only part of an overarching project to develop batteries with “new chemistry.” Basically, most battery research is angled towards high-density applications — namely, lithium-ion batteries to serve our gluttonous gadget needs. Lithium-ion batteries are very expensive, though, and are only good for a few hundred charge/discharge cycles — two factors the power grid really doesn’t care for. The grid wants huge, high-voltage batteries that can be as big as a house — and for that, you need a cheap electrolyte. Well, guess what? Stanford’s copper cathode works with a water-based electrolyte that is “basically free.” Cool.

Read more at Stanford University and Nature Communications