Annotation

The Lithium-ion battery (LIB) is an important technology for the present and future of energy storage, transport, and consumer electronics. Despite the decrease in the cost of lithium-ion batteries and a significant increase in the areas of their application, the problem of the safety of systems based on them remains no less urgent than at the time this technology entered the market. Although LIB manufacturers claim that their batteries are safe, the use of active oxidizing and reducing agents in these systems together with organic electrolytes carries the risk of fire and explosion. For example, the US Consumer Product Safety Commission reported 25,000 incidents of lithium-ion battery fires in various devices between 2012 and 2018. To reduce the risk of fire, manufacturers use internal and external battery protection methods. The external ones include the electronic battery management system (BMS), which monitors the state of each battery and the battery as a whole, internal protection methods are based on the functionalization of the battery components (electrolyte, electrodes, separator) and are aimed at slowing down or stopping the thermal runaway at a certain stage. its development. In Project 2019, a new method of protection was proposed, which makes it possible to fully secure lithium-ion batteries. For the first time, the concept of a potentioresistive protective sublayer, a thin film of variable resistance material placed between an aluminum current lead and the active mass of the cathode, was proposed. The principle of the protective action of the sublayer is based on the phenomenon of potentioresistive transition, when the film sharply increases its resistance when crossing the threshold value of the voltage applied to the electrode. Outside of the conductivity range, that is, when the cell is overcharged or overdischarged, the resistance of the sublayer rises sharply, providing a protective function against overcharging and short circuits. Compositions of materials for the formation of sublayers, providing protection of batteries based on lithium ferrophosphate, were proposed, and a scheme for the formation of protective sublayers by the method of oxidative electropolymerization was proposed. However, based on the analysis of the results obtained, new problems were identified, the solution of which is necessary to improve the developed technology for applying a protective sublayer, as well as to adapt the characteristics of the sublayer to the electrode materials of high-voltage cells. The first problem arises from the multistage electrochemical process of applying polymers to an aluminum current lead. The proposed process carries certain risks of material damage, demonstrates low productivity and high requirements for reagents, galvanic bath and the atmosphere above the electrolyte. Therefore, the project 2021 proposes replacing galvanic technology with mechanical polymer deposition, for which a chemical method for producing an electroactive polymer will be developed, which is the optimal material for protecting batteries with low-voltage cathode materials, stabilizing polymer particles in the form of a suspension suitable for mechanical deposition, as well as development of technology for coating aluminum foil using this suspension. The second task of the project arises due to the fact that the potentioresistive characteristics of the polymers found during the previous stage of the project are not suitable for creating powerful high-voltage batteries based on lithiated cobalt oxide and mixed oxides due to the too narrow conductivity range. In this regard, it is planned to search for and study new potentioresistive polymers, whose potentioresistive characteristics would allow them to be used to protect cells with high-voltage cathode materials. The class of chemical compounds, which forms the basis for such a search, was formed during the implementation of the Project 2019. Thus, within the framework of the Project 2022, work will be carried out in two directions (chemical synthesis and production of stable suspensions of polymeric materials and synthesis and characterization of new potentioresistive polymers), each of which has an absolute novelty both in synthetic terms and in terms of expected results in establishing the dependence of the properties of polymers on their structure.

Expected results