In battery designs based on the principle of liquid flow from one reservoir to another (liquid flow battery), valves and pumps are usually used to ensure the movement of the electrolyte. This electrolyte, or electrolytes of two different types, separated by an ionic membrane, move through a chamber with electrodes, on which an electric potential is created. The disadvantages of such batteries include the complexity of their design, but they have one indisputable advantage, after all the electrolyte has flowed from one container to another, for their reuse it is necessary to direct the liquid flow in the opposite direction. Using a similar principle, researchers at the Massachusetts Institute of Technology have created an "eternal" battery in which the electrolyte flows only under the influence of gravity. And in orderto “recharge” the battery, all you need to do is turn it over like an hourglass.
In a prototype battery, liquid electrolyte fills only one side of the battery, the other is filled with metallic lithium. The researchers reported that this hybrid option is an intermediate option designed to test the functionality of their idea. And in the very near future they are going to make a new prototype, inside which there will be only a liquid electrolyte. Nevertheless, there is a future for such a hybrid battery, because this approach will allow the creation of highly efficient energy sources and devices that will take the best features of solid-state and liquid electrolyte batteries.
The apparent simplicity of the design of the new battery is very deceiving. To create it, scientists had to delve deeply into the intricacies of the movement of fluid flows, find the optimal composition of the liquid electrolyte and develop the design of the battery itself. But all the efforts spent were worth the result, because the resulting source of electrical energy is simple and less expensive than other similar solutions.
The design of the new battery is scalable, it will be possible to create arbitrarily large modular systems on its basis, which will act as a buffer between variable energy sources, such as the sun and wind, and end users. “We were able to build a bridge between two completely different areas, between fluid dynamics and electrochemistry,” the researchers write. “Liquid transfer equipment accounts for the bulk of the cost of liquid batteries. And our technology allows you to completely get rid of this."
