INFINE

The efficiency of electrochemical energy storage devices (EESDs), namely batteries and supercapacitors, strongly depends on the properties of electrode materials. Therefore, there is necessity of development of synthetic strategies allowing fine control on such material properties as conductivity, crystallinity, nanostructuration, specific surface area, chemical surface composition, electrochemical stability, charge storage capacitance and structural flexibility upon charge storage. The project INFINE combines the expertise of 4 research teams in the synthesis of different inorganic materials with focus on their application as electrodes in EESDs. The central object of the project is F-TMO/C: the composite materials based on transition metal oxides (TMO) of Mn and Fe combined with carbon, and subjected to surface fluorination to improve the interface electrode/electrolyte of EESDs. We shall apply different synthetic strategies allowing preparation of materials with strong electrochemical performance, control of their properties, and favorable from the viewpoint of sustainable development and scalable process. The ultimate goal of the project is to establish a correlation between the conditions of synthesis of materials, their structural and textural characteristics particularly at the interface TMO/ C and TMO/C/F, and their electrochemical performance in EESD (supercapacitors and batteries). For the preparation of carbon components of composite TMO/C, we shall focus on carbon aerogels (CAs) and few-layer graphene (FLG). FLG can be prepared from relatively cheap and abundant graphite by sonochemical route. CAs are the materials prepared by versatile sol-gel route. Employing these methods, CAs and FLGs with controlled porosity and surface composition can be prepared. Carbon materials with high conductivity and stability, optimized specific surface area, porosity and chemical surface composition will be used as electrodes in EESD: supercapacitors and Li batteries. They also will be utilized as a component of composite materials with TMO. The latter have high energy density due to conversion process (batteries) and pseudocapacitance (supercapacitors) phenomena; however, careful control on their nanostructure and crystallinity is required. We shall focus on preparation of crystallized nanoparticles (10-20 nm) of oxides of Fe and Mn: more abundant than currently commonly used Co oxides. Oxides of Mn are known to have high energy storage density; oxides of Fe have smaller energy density, but, in general, very stable electrochemical performance. Binary spinel oxides as well as substituted spinel with varied compositions will be prepared. Two main methods of synthesis of TMO/C composites, allowing fine control on the nanostructure, composition and crystallinity of TMO nanoparticles will be employed: solid state combustion and hydrothermal polyol methods. These methods are often used for the synthesis of TMO materials; their application for TMO/C composites has been recently explored and set them as promising candidates. Finally, TMO/C composites will be modified by gas-phase fluorination. This approach has been shown to improve conductivity and electrochemical stability of TMO materials, thus boosting their electrochemical performance. Detailed study of electrochemical properties TMO/C materials before and after fluorination will allow to understand the mechanism of fluorination and its effect on electrochemical performance of materials. Consortium of the project involves the specialists in the different synthetic approaches toward inorganic materials. Combination of the expertises of partners of this project will provide deeper understanding of the links between the properties of materials their interfaces and their electrochemical performance, and will results in new types of electrode materials.