{"id":12368,"date":"2020-05-01T15:49:15","date_gmt":"2020-05-01T13:49:15","guid":{"rendered":"https:\/\/hiu-batteries.de\/researches\/research-groups\/composites-hybrid-materials\/"},"modified":"2021-10-29T13:21:37","modified_gmt":"2021-10-29T11:21:37","slug":"composites-hybrid-materials","status":"publish","type":"page","link":"https:\/\/hiu-batteries.de\/en\/researches\/research-groups\/composites-hybrid-materials\/","title":{"rendered":"Composites & Hybrid Materials"},"content":{"rendered":"\t\t
The scientific goal of the research group Composites \/ Hybrid Materials is the (further) development of innovative electrode materials for the next generation of batteries. It utilizes extremely different methods of preparation, such as solid-state reactions, sol-gel reactions, and hydrothermal reactions, to determine the most effective of theses method leading up to a highly pure final product. Furthermore, physical and structural characterizations are conducted to determine the influence that the morphology as well as the configuration of the atoms plays on the electrochemical properties.<\/p>\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t
Optimizing the materials for electrodes poses a great challenge to battery research. To do this, different methods of preparation\u2014among other things\u2014have to be developed. Many fundamental issues have to be resolved before high-purity products can be produced on a laboratory scale. The electrochemical properties of the materials are determined by their internal structure, down to the atomic level. Both the interface between the electrode and the electrolyte and its properties exert an influence on decomposition reactions, which greatly compromise a battery’s performance.<\/p>\n
The research group Composites and Hybrid Materials is achieving a fundamental understanding of how electrode materials develop, in order to be able to decisively help develop the next-generation battery.<\/p>\n<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t
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Various methods of preparation are employed, such as solid state, sol-gel, and hydrothermal reactions, in order to determine which of these methods is the most effective to ultimately obtain a high-purity end product. Furthermore, physical and structural characterizations are conducted to determine the influence of the morphology, the configuration of the atoms, on the electrochemical properties. The most important starting point for this is to understand the different factors exerting an influence\u2014based on the various underlying syntheses\u2014on the structure, the electrochemical properties and their electrode\u2013electrolyte interface, the properties of the surface, and possible decomposition reactions.<\/p>\n
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For this purposes, very different methods of characterization are employed, such as X-ray diffraction (XRD), inductively coupled plasma emission spectrometry (ICP-OES), and scanning electron microscopy (SEM).<\/p>\n
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Another activity of this group is the development of innovative concepts for the optimized synthesis of carbon nanocomposites or conductive layers.<\/p>\n
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Lithium-ion battery technology has found many applications, but it is limited by the insertion reaction that takes place with many materials and the associated transfer of at most one electron per ion of transition metal. This in turn ultimately limits the specific energy of the batteries. The reason for the interest in multistep redox materials results from the fact that these materials are capable of an insertion\/extraction of more than one lithium ion per formula unit.<\/p>\n
This concept has previously only been confirmed for two-dimensional nanostructures (i.e., ultrathin film) and is now to be transferred to three-dimensional ones. To reach this goal, various approaches have been developed, such as the use of a modified sol-gel or hydrothermal approach (with the addition of a surfactant) for the synthesis of high-purity Li2<\/sub>Mex<\/sub>Me(1-x)<\/sub>SiO4<\/sub>\/C composite materials (A and B).<\/p>\n \u00a0<\/p>\n A reduction in particle size and the addition of a nanolayer of carbon is indispensible for attaining good rate and cycle stability because of the low electronic and ionic conductivity of most of the innovative electrode materials. In order to create such a nanolayer of carbon on the materials, our group developed two different processes:<\/p>\n Regardless of the method, the addition of carbon reduces the material’s energy density. Effective routes for preventing this are being examined in order to design innovative structures that contain spherical, aggregated, or compact nanocrystallites. The precise role of carbon has, moreover, not yet been completely understood and is also being studied using various analytic techniques.<\/p>\n<\/div><\/div> (information will be uploaded shortly)<\/p>\n<\/div><\/div> (information will be uploaded shortly)<\/p>\n<\/div><\/div>In situ\/ex situ carbon coating of lithium metal-silicate materials<\/h2>\n