The electrochemical properties of two fluorinated substrates, namely 1H-3-methyl-4-ethoxycarbonyl-5-(4-fluorobenzylidenehydrazino)-pyrazole (Ia) and 1H-3-methyl-4-ethoxycarbonyl-5-(2-fluoro-benzylidenehydrazino)-pyrazole (Ib) respectively have been investigated in the room temperature ionic liquid (RTIL) 1-butyl-3-methylimidazolium tetrafluoroborate on a platinum electrode.The voltammetric investigation of the above compounds in the mentioned RTIL shows mainly two irreversible anodic peaks on a wide range of scan rates.Mechanistic studies involving the estimation of the diffusion coefficient, number of transferred electrons in the rate-determining step as well as charge transfer coefficients show that the main aspects of the anodic oxidation of the given substrates follows an EC mechanism which is similar to that observed in molecular solvents leading to the assumption that oxidative ring closure reactions may be conducted in RTILs as well, providing a starting point in finding a new more sustainable method of obtaining the latter compound.The aim of the present work is to extend the current findings gathered previously in order to find a more environmentally friendly and sustainable way of obtaining various pyrazolotriazoles.
Lithium ion batteries play an important and indispensable role in the current technology thanks to the development of wearable electronics and also thanks to the increasing interest in electric vehicles. It will be necessary to replace the currently used electrode materials with new materials with higher capacity and energy density for further development in these areas, such as high-voltage batteries, lithium-sulphur batteries or Li-Air batteries. Lithium-sulphur batteries are very promising due to their high capacity and easy availability of materials. The theoretical capacity of sulphur is 1675 mAh/g and energy density is higher than 3200 Wh/kg. This system suffers by many problems. There is almost 80 % volumetric expansion during cycling on cathode or shuttle effect. Shuttle effect is probably the biggest problem of this system. Formation of polysulfides (Li 2 S 8 , Li 2 S 6 , Li 2 S 4 etc.) takes place during charging and discharging. These polysulfides are soluble in the electrolyte and they are subsequently deposited on the anode. This process leads to the decrease of capacity and cycle life of the battery. There are many ways how to prevent this process as encapsulation of sulphur in carbon in the case of formation of the barriers on the surface of electrode or separator. Another possibility is using 3D structured cathodes. These 3D structures can keep polysulfides inside the electrode and prevent capacity decrease during cycling. A biological material with high porosity was used in this article to create a 3D structure into which sulphur was incorporated by different methods as coating or precipitation. These electrodes were cycled at various loads and compared with a standard electrode. 3D electrodes show higher stability than standard electrode and higher area capacity of more than 2 mAh/cm 2 . This research has been carried out in the Centre for Research and Utilization of Renewable Energy (CVVOZE). Authors gratefully acknowledge the financial support from the Ministry of Education, Youth and Sports of the Czech Republic under NPU I programme (project No. LO1210), BUT specific research programme (project No. FEKT-S-14-2293) and in part financially supported by the Ministry of Education, Youth and Sports of the Czech Republic under the project CEITEC 2020 (LQ1601).
