Liquid Battery for Solar Energy Storage

One of the biggest challenges currently facing large-scale solar energy technology is finding an effective way to store the energy, which is essential for using the electricity at night or on cloudy days. Recently, researchers from MIT have designed a new kind of battery that can quickly absorb large amounts of electricity, as required for solar energy storage. Unlike conventional batteries it is made of all-liquid active materials. The battery consists of three layers of liquids: two electrode liquids on the top and bottom and an electrolyte liquid in the middle forming the three distinct layers. In the first prototype, the electrodes were molten metals - magnesium on the top and antimony on the bottom - while the electrolyte was a molten salt such as sodium sulfide. When charging, the solid container holding the liquids collects electrons from exterior solar panels or another power supply, and later, for discharging, the container carries the electrons away to the electrical grid to be used as electricity. As electrons flow into the battery, magnesium ions in the electrolyte gain electrons and form magnesium metal, rising to form the upper molten magnesium electrode. At the same time, antimony ions in the electrolyte lose electrons and sink to form the lower molten antimony electrode. At this point, the battery is fully charged, since the battery has thick electrode layers and a small layer of electrolyte. To discharge the electrical current, the process is reversed, and the metal atoms become ions again. The batteries are expected to be inexpensive and simple to manufacture but likely to have the inherent problems associated with handling of liquids.