The problem with renewable energy sources is that wind and solar power are intermittent — it's too unreliable to power an entire grid constantly, but a new kind of cost-effective battery could make wind and solar power more widespread. Ambri, a start-up, has produced a new kind of battery with components made out of liquid metal.
A container 16 inches in diameter, made out of thick steel, encases a mixture of magnesium and antimony in this new kind of battery. The two elements separate naturally when in liquid form — magnesium will float to the top and a liquid-salt electrolyte layer sits between the magnesium and antimony.
Magnesium from the top layer acts as the anode, Technology Review reports, and when called on to deliver power, will give off electrons which subsequently travel through the salt mixture and interact with antimony to form an alloy (the cathode). When the battery charges, separating magnesium from the alloy and sending it back to the top, the flow of current generates enough heat to keep the battery components in a molten state. Ambri has since switched to cheaper metals and a salt mixture.
Because grid batteries are not limited by weight or size, Ambri co-founder Donald Sadoway, a professor of materials at MIT, developed liquid-metal cells as an alternative. It could be produced using abundant, inexpensive materials in a simple process, and deliver power safely — either in quick bursts or for longer periods. By providing an efficient way to store energy, several fossil-fuel plants can be closed as the batteries pick up the slack.
The company plans to avoid utility companies in favor of independent power producers once the battery becomes commercially available (it's still in its prototype stage). For instance, in west Texas, electricity is cheapest and most abundant at night, when few people are using it. The excess goes to waste, but with higher-capacity batteries, the energy could be saved for peak hours and sold for a better price. Today's storage options are massively inefficient, running on a system whereby water is pumped uphill to a reservoir during off hours and let out when needed. It is limited to places with mountains and a lot of water.
Unlike batteries with solid electrodes that degrade over time, the liquid-metal version could last for years without losing storage capacity.
