Lithium-ion batteries are something unknown for just those who live far from civilization: they are used in mobile phones, laptops and cameras, and the most powerful are used for electric transport and even for aerospace industry. Today the third generation of Li-ion is mainly in use; most of them are made on the basis of graphite and Lithium iron phosphate. To be one step ahead of all the other developers, scientists of P.G. Demidov Yaroslavl University (jointly with the RAS A.N. Frumkin Institute of Physical Chemistry and Electrochemistry and Yaroslavl branch of RAS Physics and Technology Institute) are developing the lithium-ion batteries of the fourth generation, which have a much greater capacity and more power. Works on the project, led by Alexander Rudoi, YSU Professor, are supported by the Federal Target Program "Research and development 2014-2020".
Most modern batteries are manufactured according to the so-called "pasted" technologies - that is, on the basis of thick-film electrodes having a large surface area of contact with the electrolyte, so that the size and weight of the battery are generally small. They are able to work in the cold, and almost dont discharge in absence of direct energy consumption. However, the capacity of these batteries is limited by the specific capacity of graphite (372 mAh / g) and Lithium iron phosphate (150 mAh / g).
Device proposed by YSU scientists implies the creation of new thin-film batteries based on silicon nanocomposites and higher oxides of vanadium.
A new electrochemical system has high electric capacity and speed of charge: it is connected with a capacity of silicon, the theoretical limit of which is 4212 mAh / g, and of vanadium pentoxide - 883.5 mAh / g. At the same time the fourth generation batteries will have been produced on not the "pasted" technologies, but on technology of integrated electronics, by vacuum deposition methods. Therefore, the main efforts of the development team aimed at solving several technological challenges of thin-film batteries manufacturing: first, during the intercalation of lithium ions (i.e. during the current-producing reactions) specific volume of silicon is tripled - and as a result, silicon is destroyed; and secondly, creation of a homogeneous film of vanadium pentoxide has not been possible yet. In this case, battery recharge with the cathode made of vanadium oxide (or, in scientific terms, the reversible introduction of lithium) is possible in either very thin or nanoporous films.
«At the moment we are the only researchers who managed to get a stable thin-film electrodes, withstanding up to 500 cycles of charge-discharge cycles», - Alena Metlitskaya, a young scientist and member of the project told. - You can consider it a kind of breakthrough in the field of chemical power supply sources". YSU scientists and RAS scientific institutions has been working on this topic for some years, so that only the students of the 3rd course, who have recently started working on the project, have had no publications yet. The publications amount of all the other researchers, working on the project, varies from a few to several hundred.
In addition, developers have already received two patents for methods of manufacturing thin-film anode and cathode and are conducting patent research now to find out the patentability of new technical solutions. These solutions include emerging lithiation technologies of one of the electrodes during the deposition process and manufacturing of solid-state electrolyte.
Of course, scientists are exclusively engaged in research and technological part of the project. "Our task is to develop the domestic manufacturing technology for lithium-ion batteries of the fourth generation and to transfer the technology to industrial partner," - Metlitskaya says. The implementation of domestic batteries production will be brought about by commercial and industrial partner of the scientific team - JSC "Safonovsky plant" Gidrometpribor" in the Smolensk region, which is producing barometers, weather stations and recorders today.