Liquid and solid-state batteries each have their own advantages and disadvantages, but now researchers at the University of Texas at Austin claim to have developed a new battery that mixes the best of both worlds. The new design is the first all-liquid-metal battery that can operate at room temperature, and it apparently outperforms lithium-ion batteries.

Liquid metal batteries have electrodes made of – you guessed it – liquid metals. These devices are less susceptible to wearing out than solid batteries, since dendrites don’t form and damage the components. Plus, they’re simple to scale up – just add more liquids in bigger tanks.

But there’s one major downside: temperature. In order to keep the metals liquid, most of these batteries need to be heated to at least 240 °C (464 °F). The equipment needed to do that makes the devices bulky and energy-consuming.

But for the new study, the team investigated alloys that could remain liquid at more useful temperatures. They settled on two that worked well, using a sodium-potassium alloy for the anode, and a gallium-indium alloy for the cathode. These were able to remain liquid at just 20 °C (68 °F), which the team says is the lowest operating temperature for any all-liquid-metal battery.