Researchers have built a new type of battery that combines the benefits of existing options while eliminating their key shortcomings and saving energy. Most batteries are composed of either solid-state electrodes, such as lithium-ion batteries for portable electronics, or liquid-state electrodes including those for smart grids. The researchers have created a “room-temperature all-liquid-metal battery,” which includes the best of both worlds of liquid-and solid-state batteries.
Solid-state batteries feature significant capacity for energy storage but they typically encounter numerous problems that cause them to degrade over time and become less efficient. Liquid-state batteries can deliver energy more efficiently without the long-term decay of sold-state devices; however, they either fall short on high energy demands or require significant resources to constantly heat the electrodes and keep them molten.
The metallic electrodes in the new battery can remain liquefied at a temperature of 20 °C (68 °F) — a major change because current liquid-metal batteries must be kept at temperatures above 240 °C.
The battery includes a sodium-potassium alloy as the anode and a gallium-based alloy as the cathode. It may be possible to create a battery with even lower melting points using different materials.
Because of the liquid components, the battery can be scaled up or down easily, depending on the power needed —the bigger the battery, the more power it can deliver. That flexibility allows these batteries to potentially power everything from smartphones and wearable devices to the infrastructure underpinning the movement toward renewable energy.
Many of the elements that constitute the backbone of the new battery are more abundant than some of the key materials in traditional batteries, making them potentially easier and less expensive to produce on a large scale; however, gallium remains an expensive material. Finding alternative materials that can deliver the same performance while reducing the cost of production remains a key challenge. The next step to increasing the power of the room-temperature battery comes in improving the electrolytes — the components that allow the electrical charge to flow through the battery.