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A new laboratory lithium ion cell in two electrode arrangement has been developed in order to apply in-situ short-term thermal stress tests to both electrodes. Cells were made from commercially available LiCoO 2 cathodes, graphite anodes and electrolyte. A 60 s thermal stress was applied with different temperatures ranging from 100 to 250 • C at the anode side after the cell formation and capacity tests. By comparison of the charge-discharge behavior of the cells before and after the thermal stress, capacity losses, increasing overvoltages and self-discharge have been observed as a function of the stress temperature. For detection of changes in the anode properties scanning electron microscopy (SEM), thermogravimetric analysis (TGA) and computed tomography (CT) characterizations were used, and changes in the morphology and composition of the solid electrolyte interfaces (SEI) layer were observed. Long term cycling and the corresponding capacity and power fade in lithium-ion batteries has recently been extensively studied.1,2 Several aging mechanisms on the single components are proposed in the literature. The degradation reactions are complex, coupled, and dependent on cell chemistry, design and manufacturing procedures used. 3Many studies report the thermal behavior and stability of single components, revealing that elevated temperatures could cause irreversible damage to the materials. [4][5][6][7] Lithium-ion cells face multiple production processes during the fabrication of a high-end battery system, such as contact welding. Depending on the welding technique, the cells are briefly exposed to elevated temperatures of up to several hundred• C. However, to our knowledge no information is available about the influence of such short-term thermal stress conditions on the cell performance and components properties.In the current contribution the anode side of a single lithium cobalt oxide/graphite Li-ion cell was thermally stressed for 60 s at different temperatures and the effects of short-term thermal stress were demonstrated for the first time. To conduct the study a new laboratory cell was developed, allowing in-situ thermal stress tests on both electrodes. The present manuscript is an extended version of the manuscript submitted to the International Meeting on Lithium Batteries 2014 issue of ECS Transaction, 62 (1) 189-196 (2014). ExperimentalMaterial.-Commercially available LiCoO 2 cathodes and graphite anodes from MTI Corporation (Richmond, USA) were used. According to the material specifications provided by the supplier, the anodes contain composite graphite as active material with specific area of 3∼5 m 2 /g and specific capacity of 330 mAh/g. The active material loading is 80 g/m 2 . The active material used in the cathode is LiCoO 2 with specific capacity of 145 mAh/g and loading of 200-250 g/m 2 . A standard aprotic electrolyte LP 30 (BASF, Ludwigshafen, Germany) was used containing 1 M LiPF6 and ethylene carbonate (EC) and dimethyl-carbonate (DMC) in ratio 1:1. A 25 μm trilayerd polypropylene/polyethy...

Resist based lithographical techniques are widely applied for graphene processing. These resists can leave residues leading to parasitic effects that deteriorate the desired properties of graphene. This paper presents an experimental setup tailored for resist-free robotic processing of graphene with in-situ vision based control. A robust graphene detection and classification approach is presented applying multiple image processing operations of the visual feedback provided by a high-resolution light microscope. Detected graphene flakes can be modified using scanning probe based lithographical processes, such as mechanical and bias-assisted approaches, that are directly linked to the in-situ optical images. The results of this process are discussed with respect to further application scenarios.

This paper presents a nanorobotic platform tailored for rapid prototyping of graphene based devices. Applying the capabilities of this platform, a nanorobotic strategy is proposed that enables the identification, electrical characterization and integration of graphene into device structures without using any time-consuming lithography procedures. In this way, graphene based devices can be fabricated and classified within few hours, significantly reducing the effort and consequently the costs of device prototyping. As an example of this strategy, graphene flakes are characterized and subsequently transferred onto trench structures resulting in partially suspended areas suitable to study graphene based nanoelectromechanical systems.

Using high resolution computed tomography (CT) the change of the morphometric parameters in depth of electrodes for lithium ion batteries with aging has been examined. Commercially available 2 Ah Li-ion cells were continuously cycled to different state of health (SOH). The cathodes were subsequently analyzed using CT with voxel size resolution of about 400 nm. For a quantitative analysis binarized images were evaluated and various properties such as the size distribution of active particles analyzed. Using this technique a decrease in the average particle size and an increase in number of particles of LiCoO2 with decreasing SOH of the battery is confirmed experimentally for the first time.

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