Japanese researchers have almost completely restored the capacity of lithium batteries with the help of a substance that repairs damaged electrodes. The scientists’ discovery will extend the life of such batteries and therefore reduce the amount of hazardous waste.

In the modern world, lithium batteries are used in everything from home electronics to electric cars. These types of batteries have many advantages: they charge quickly, have low self-discharge and are maintenance-free. However, there are also disadvantages. The main ones are the limited service life, usually between 500 and 2000 charge-discharge cycles, and the danger they pose to humans and the environment.

As lithium batteries age, they “lose” some of the electrode material that allows them to store energy, reducing energy consumption. As a result, batteries are either thrown into landfill (they emit harmful substances during the decomposition process and can sometimes catch fire or even explode) or are given to companies that deal with their disposal. Experts disassemble the batteries, extract the materials, and then subject the extracted raw materials to secondary processing.

However, disposal of lithium batteries is a time-consuming, expensive and energy-intensive process. Therefore, scientists have long been looking for ways to reduce the number of processing stages. One of the solutions was proposed by Japanese engineers from the T research institute. oyota Central R&D Laboratories., Inch. — Battery capacity recovery technology that does not require disassembly.

This technology is based on injecting certain reagents into the spent cell, which, although not correcting the structural damage accumulated in the battery, reverses the chemical aging of the battery by regenerating the electrochemically active material. The results of the study were published in the journal Joule.

Commercial lithium batteries consist of several main components. First, these are two electrodes with opposite signs: an anode made of graphite and a cathode made of lithium oxide. There is a fine-mesh separator between the anode and cathode, which prevents the two electrodes from short-circuiting. The battery also has an electrolyte made of organic solvents and based on lithium salts, which allows lithium ions to move within the cell.

During charging, an electric current moves lithium ions from the cathode to the anode. When the battery is used (during discharge), the ions return to the cathode. Over time, this whole process leads to corrosion of the cathode (its material cracks and can no longer hold the original number of lithium atoms), as a result of which the battery capacity begins to decrease, that is, energy is no longer stored in it. Very good. This means that each time the battery is charged, its maximum lifespan is shortened by a few seconds.

Japanese scientists tried to “regenerate” this electrochemically active material in a depleted battery. To do this, the researchers tested several possible reducing reagents, which are substances that produce electrodes during chemical reactions. Experiments have shown that the lithium naphthalene-based reagent can increase the amount of workable anode and cathode material in the battery and restore the battery to 80 percent of its original capacity. This capacity was maintained for 100 charge-discharge cycles.

According to the authors of the study, the new method will make it possible to extend the life of lithium batteries several times. Instead of being thrown away or subjected to complex and expensive disposal, used batteries can be brought back to life and used in the same electric vehicles or other devices.

Scientists tested the new recovery technology not only on small batteries but also on large car batteries. It has proven itself well in both cases.

But some experts are skeptical of the colleagues’ discovery. According to engineer Jacqueline Edge (Jacqueline Edge) from Imperial College London, before claiming success, it is necessary to conduct a series of long-term studies to understand the possible side effects of using chemicals.

“The method proposed by Japanese engineers is only suitable for batteries that have suffered a very specific degradation. Edge noted that this method is only useful if you know the history of the battery or can diagnose its condition using simple methods that do not destroy the battery.”

Toyota Research Group applied for a patent. A number of companies and government organizations have already shown interest in the Japanese engineers’ technology. Among the latter is the American Agency for Advanced Energy Research.