A supercapacitor is an electronic device that stores and releases energy. It has a layer of electrolyte-a solid, liquid, or conductive material between solids and liquids. Now, the Massachusetts Institute of Technology (MIT) has worked with several institutions to develop a new liquid that may improve the efficiency and stability of such equipment while reducing flammability.
Researchers say the study may represent a new paradigm for electrochemical energy storage. Decades ago, researchers had discovered a new material-ionic liquids (liquid salts in nature), but the team added a compound to such ionic liquids that interacts with the surface activity of dispersed spilled petroleum Agents are similar. With the addition of the compound, ionic liquids "have very novel properties and become very viscous." The researchers said: "It is difficult to imagine that this viscous liquid can be used to store energy, but we found that once the temperature was increased, the Liquids can store more energy than many other electrolytes. "
But in fact, this is not very surprising, because as other ionic liquids increase in temperature, the viscosity will decrease and the ability to store energy will also increase. However, the current situation is that although the viscosity of the ionic liquid is still higher than that of other known electrolytes, its capacity still increases rapidly with increasing temperature. Eventually, its overall energy density exceeds that of many traditional electrolytes, Stability and security are also higher.
The efficient energy storage capacity of the liquid stems from the fact that the molecules inside it are aligned automatically, and eventually a layered structure is formed on the surface of the metal electrode. Such molecules have a tail at one end. After the arrangement, the head heads towards or away from the electrode, and the tail will gather in the middle to form a sandwich-like structure called a self-organizing nanostructure.
Such highly ordered structures prevent the occurrence of "transitional filtration", which may occur in other ionic liquids. When it occurs in other ionic liquids, the first layer of ions (charged atoms or molecules) gathered on the surface of the electrode contains more ions than the corresponding charge on the surface, resulting in a more dispersed ion distribution or a thicker ionic layer , Resulting in low energy storage efficiency. However, due to the special structure of the liquid made by researchers, the charges are concentrated on the surface of the electrode.
Researchers refer to this new material as SAILs, or surface-active ionic liquids, which have a variety of applications in high-temperature energy storage, such as in high-temperature environments such as oil drilling or chemical plants. "Our electrolytes are very safe and perform better at high temperatures, and some electrolytes in lithium-ion batteries are very flammable."
The researchers said the material could help improve the performance of supercapacitors. Supercapacitors can be used to store electrical energy, sometimes supplementing electric vehicle battery systems, and provide additional power to electric vehicles. Compared with conventional electrolytes, the energy density of supercapacitors using this new material has increased by 4 to 5 times. Compared with batteries, the use of new electrolytes may allow future supercapacitors to store more energy and may even replace batteries in applications such as electric vehicles, personal electronics, or grid-level energy storage facilities.
In addition, the material may be used in a variety of emerging separation processes. Many newly developed separation processes require electrical control, such as in various chemical processing and refining applications such as capturing carbon dioxide and recovering resources from waste, and such highly conductive ionic liquids are well suited for such applications.
The researchers' initial materials were just one possibility of SAIL compounds, and the team will continue to develop different possible compounds and optimize parameters for specific uses.