Charges for the mind: nanoswitches will help create "non-explosive" energy-intensive batteries

Russian scientists have perfected one of the key elements of modern lithium-ion batteries — a separator that separates the zones through which charged particles move. Silicate nanoparticles were added to the new sample, which provided increased strength, resistance to high temperatures, and better wettability with electrolyte, the liquid component of the battery. The development will increase the life of batteries, increase their energy intensity and the ability to hold a charge. According to experts interviewed by Izvestia, modified devices will be safer and better protected from the risk of explosion.

What are nanoswitches?

Scientists from the A.F. Ioffe Institute of Physics and Technology of the Russian Academy of Sciences (St. Petersburg) and the Kurchatov Institute - PIAF - IVS branch of the Scientific Research Center (St. Petersburg) have modified one of the key components of batteries, which will extend their service life and make them safer and more energy—intensive.

Modern devices, from mobile phones to space equipment, use lithium-ion batteries. Their stored energy density is higher than that of their analogues (for example, nickel-cadmium ones), and therefore they discharge more slowly, charge faster and, moreover, weigh less. However, despite its many advantages, lithium-ion power supplies are prone to overheating, and under certain circumstances they can even explode, the scientists said.

Battery safety is ensured by separators, which are elements that separate positively and negatively charged parts of the battery. Currently, they are produced mainly from porous polymer films, most often polyethylene and polypropylene. The main disadvantage of such materials is that when heated above 120 ° C, they are prone to shrinkage, that is, to shrink in size, which can lead to battery failure. In addition, these films are poorly wetted by polar solvents, which form the basis of the electrolyte, which impairs the movement of ions and reduces the efficiency of the battery.

Neuro interest: Brain activity reader for VR will prepare space tourists

How will the new device help train specialists to remotely control equipment on other planets?

To synthesize a special coating, the authors used a hydrothermal process that allows them to approach the conditions of formation of natural minerals in the earth's crust. The researchers coated the separator with a hydrosilicate compound containing silicon, oxygen and water. A suspension of nanoswitches, ultrathin atomically flat sheets of material that researchers have learned to fold into compact cylindrical structures resembling scrolls, was applied to its surface with the addition of a polymer binder. This treatment has significantly improved the wettability and mechanical properties of the composite membrane.

— We plan to continue modifying polyolefin separators (thin porous membranes made of polyethylene) with synthetic hydrosilicate particles with different structures and morphologies in order to improve their performance. Next, we intend to create separators based on nonwovens with embedded hydrosilicate particles with high porosity for operation at high charge and discharge currents," said Andrey Krasilin, a leading researcher and head of the Laboratory of New Inorganic Materials at the A.F. Ioffe Institute of Physics and Technology of the Russian Academy of Sciences.

In the future, scientists want to try to create a separator with a minimum thickness based on particles of layered silicates and an organic binder, which will favorably affect the size of the battery as a whole.

How to make safe batteries

Creating more stable separators is one of the key ways to improve the safety and service life of lithium—ion batteries, Alexey Salimon, head of the Department of Physical Chemistry and Deputy Head of the Accelerated Particle Laboratory at NUST MISIS, told Izvestia. In this case, the use of magnesium-silicate nanoparticles in the form of flat and rolled flakes allows us to solve several important tasks at once: to improve mechanical strength, reduce the risk of thermal shrinkage and ensure a more uniform distribution of ions.

— All this directly affects the durability and safety of batteries, especially in devices operating at high currents or at elevated temperatures. Work is underway worldwide to extend battery life: new materials for electrodes are being created, more stable liquid and solid electrolytes are being developed, as well as new types of separators and battery architectures. The common goal of all these areas is to make batteries more durable, safer and able to work in more difficult conditions," the expert noted.

The research is aimed at solving one of the main problems of lithium-ion batteries: how to make them more durable, safer and long-lived. The new separator with silicate nanotubes withstands heat better, does not tear and is better impregnated with electrolyte, due to which the capacity lasts longer and the charge lasts better, said Maxim Dorogov, associate professor at the Institute of Advanced Data Transmission Systems at ITMO.

— Today, several areas are developing at once to increase battery life. On the one hand, lithium-ion batteries themselves are being improved: the materials of the electrodes and separators are being refined so that they can withstand more charging and discharging cycles without significant degradation. On the other hand, the so—called post-lithium systems are actively developing - sodium-ion, potassium-ion and others. Although they are sometimes inferior to lithium-ion in terms of energy intensity, these technologies benefit in terms of cost, safety and stability," the specialist noted.

Both fish and meat: a special form of animal protein will help against liver fibrosis and scars

How powder Additives accelerate tissue regeneration and reverse biological processes

According to him, ITMO is also conducting research related to materials for batteries and their "life cycle." The institute has created a special membrane that helps to almost completely extract lithium from used batteries and industrial solutions. This approach not only reduces the burden on the environment, but also returns valuable metal back to production, closing the cycle from creation to processing of raw materials.

The results of the study, supported by a grant from the Russian Science Foundation (RSF) and the St. Petersburg Science Foundation (SPbPF), are published in the Journal of Power Sources.