It sounds simple, but there was a challenge to making this work. The team had to use a ceramic membrane that combined aluminum oxide and potassium to separate the positive and negative materials while still allowing a current.

There's still some tweaking left, such as optimizing the membrane to improve the power output and choosing a liquid for the positive side that won't weaken the membrane. And like many battery experiments, there's a long road from a successful lab test to something you can buy. There's a strong incentive to make this a reality, though. If it lowered the price of storage batteries, both homeowners and electrical grid operators might be more likely to switch to solar or wind power knowing that they'd recover their investments that much sooner.