The gas evolution related to the film formation on cathode materials for lithium-ion batteries was studied using differential electrochemical mass spectrometry and subtractively normalized interfacial Fourier transform infrared spectroscopy. With both methods the oxidative formation of CO 2 was observed in standard battery electrolytes. We show the strong influence of the type of the electrolyte and especially of the additive, vinylene carbonate ͑VC͒, as well as the effect of the temperature on the CO 2 gas formation rate. The VC additive significantly reduces the gas formation rate in the commonly used voltage window between 3.0 and 4.3 V. Long cycling experiments show that test cells containing VC have a higher cycling stability compared to cells cycled without this additive. Cycling at elevated temperatures ͑60°C͒ results in a high, enduring CO 2 gas evolution, already starting at a lower cell voltage of about 3.5 V.In the current generation of commercially available lithium-ion batteries, graphitic carbon is used as the anode material and insertion oxides as the cathode material. The electrochemical potential of both electrode materials is far beyond the thermodynamic stability window of the commonly used organic electrolytes. Hence, reductive and oxidative electrolyte decomposition occurs, leading to gas evolution in the electrochemical cell. This process increases the internal cell pressure, which may raise the safety risk due to possible cell leakage. The calendar life of the cell would be shorter, too. Fortunately the solid electrolyte interphase ͑SEI͒ formed at the surface of the negative electrode material prevents further reductive electrolyte decomposition. A similar protective film is also reported for positive electroactive materials such as LiMn 2 O 4 and LiCoO 2 , but the two-decades-old discussion about the SEI on positive electrodes is still controversial and the influence of this film formation process on the behavior of the cells is still a matter of intense investigations. [1][2][3] Different in situ methods like Fourier transform infrared ͑FTIR͒ and Raman spectroscopy as well as scanning electron microscopy ͑SEM͒ have been successfully introduced for the examination of film formation on the electrode surface. 4-9 Recently we were able to show that it is possible to observe the film formation on cathode materials with post mortem SEM. 10 The results of this work proved that various parameters like type of cathode material, electrolyte composition ͑in particular the application of certain additives͒, and the temperature affect the extent of the formation of the cathodic SEI. From investigations on graphite anode material it is known that the film formation is often accompanied by gas evolution. 11-13 The same has also been reported for different cathode materials. 14 It has been shown that primarily CO 2 is formed by oxidative decomposition processes on the oxide surface. 15 Obviously, in an extreme case the CO 2 evolution could lead, over a longer period of time, to a reduced life time of the...

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A sequential injection-capillary electrophoresis (SI-CE) system for the fast and automated quantitative analysis of anions and cations is described. Because of the low sample load in capillary electrophoresis a split injection approach had to be used to achieve reliable hydrodynamic injection. The use of a capillary of 8 cm effective length allowed for the separation of five inorganic cations within 11 s. One common electrolyte solution containing 12 mM l-histidine and 2 mM 18-crown-6 whose pH value was adjusted to 4.0 with 10% v/v acetic acid was used for anions and cations, thus the analysis of both groups of analytes could be carried out in rapid sequence simply by switching the polarity of the high voltage supply. The system also allows automated flushing of the capillary. Detection limits between about 2 and 5 micromol l(-1) could be achieved with the contactless conductivity detector employed.

While the cost of the state-of-the-art electrochemical energy storage technology, the Li-ion battery (LIB), has been reduced by 8% at the pack level annually during the last decade (1), it is nowreaching its fundamental limits in terms of energy density. Furthermore, the risk of limited lithium supply and associated cost increases cannot be ignored. Therefore, new sustainable battery chemistries must be developed. Calcium-based rechargeable batteries are proposed to help solving some of the Grand Challenges our modern society is facing: pollution, oil-dependency, and climate change. Batteries based on Ca have promise of leap-frog increase in energy densities and are especially attractive as Ca is the 5th most abundant element in the Earth’s crust and can indeed be used as a metallic anode with conventional wide potential window electrolytes (2,3). The CARBAT project builds on this breakthrough and its main objective is to achieve proof-of-concept for a Ca anode rechargeable battery. CARBAT combines scientific efforts of computational screening, solid-state and coordination chemistry, materials science, electrochemistry, and battery engineering, and apply these to: (i) develop cathode active materials operating at 4 V and with capacities of 200-300 mAh/g, (ii) optimize electrolyte formulations for fast Ca2+ transport (>1 mS/cm), and finally (iii) assemble a 100 mAh cell demonstrator. All developed materials and cells are validated and benchmarked vs. state-of-the-art LIB technology, both in terms of performance and sustainability indicators. (1) Nykvist, B.; Nilsson, M. Nat. Clim. Change, 2015, 5, 329. (2) Muldoon, J. Chem. Rev., 2014, 114, 11683. (3) Ponrouch, A.; Frontera, C.; Barde, F.; Palacin, M.R. Nat. Mater., 2016, 15, 169.

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The manufacturing process of lithium cells is a complex series of chemical and physical manufacturing and assembly steps. The value chain for lithium cells and batteries is divided into three production areas: electrode coating line (mixing, coating and compaction ) cells production line battery production line As part of a project funded by the German government S-Protrak was focusing especially on the electrode coating and parts of the cell production (separator). The developed technologies were than integrated in prototypes. For the process development existing test facilities were used in order to minimize the material costs and the expense of production integration in the available project period.  Each of the project partners worked on different tasks. Jonas & Redmann developed and evaluated system concepts and important characteristic data for inspection technology during coating processes. FMP developed solutions for integrating coating and drying systems optimized for the installation space based on diffusion-optimized convection drying. The Fraunhofer ISIT designed procedures for the direct coating of separators on electrode foils using existing patents, and the Technical University of Braunschweig focused primarily on the continuous manufacturing of electrode pastes using extrusion to increase economic and environmental efficiency.  Headed by the Fraunhofer Institute for Silicon Technology (ISIT) the S-Protrak consortium developed technologies for industrial production of cost-effective high-quality lithium cells and manufacture prototypes of these technologies. The projects plays an important role in the development of battery-powered electric vehicles and, through their work and research results, help implement the German federal government’s national development plan for electromobility and establish a German battery supplier market. Lithium batteries have undergone a significant expansion of application fields in recent years. Besides its use in electric and hybrid vehicles, this also includes stationary energy storage systems. The cell capacity has at the same time grown significantly and is now typically between 20 and 40 Ah. This is accompanied by significantly increased demands on manufacturing quality and a strong price pressure. The separator concept developed in this project takes this into account by focusing on the improvement of the quality (waste reduction) and cost reductions especially with increasing production efficiency. In addition, a significant improvement in the cell performance was expected. This can establish other fields of applications, for instance starter batteries. Core of this innovation is a direct coating of the separator on the electrode foil. This can be done either in a wet on wet process (WoW) directly on the undried electrode foil or wet on dry (WoD) after the electrodes has dried. For the development of this process, enhancements of existing coating technology, especially for the coating head as well as for the separator slurry formulation were necessary. The basic separator concept was developed and patented by Fraunhofer ISIT already in 1999. It consists of a lithium conductive ceramic that is bound by a PVDF polymer. Acetone is used as a solvent. In order to be used for a direct coating process on electrodes the slurry formulation had to be adapted, especially by increasing the viscosity without losing its performance. Therefore the mixing procedure had the be changed. Using the coating facility of Fraunhofer ISIT and a slot die coating system from FMP both processes (WoW and WoD) were developed and different coated electrode foils were produced. With these foils test cells (full and half cells) were assembled for the electrochemical characterization of the electrodes. It was possible to show a stable cycling behavior for the WoW as well as the WoD process. It is therefore possible to use this technology, especially WoW, in order to enhance the production efficiency and to reduce the costs. Figure 1