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X-ray photoelectron spectroscopy (XPS) is a key method for studying (electro-)chemical changes in metal-ion battery electrode materials. In a recent publication, we pointed out a conflict in binding energy (BE) scale referencing at alkali metal samples, which is manifested in systematic deviations of the BEs up to several eV due to a specific interaction between the highly reactive alkali metal in contact with non-conducting surrounding species. The consequences of this phenomenon for XPS data interpretation are discussed in the present manuscript. Investigations of phenomena at surface-electrolyte interphase regions for a wide range of materials for both lithium and sodium-based applications are explained, ranging from oxide-based cathode materials via alloys and carbon-based anodes including appropriate reference chemicals. Depending on material class and alkaline content, specific solutions are proposed for choosing the correct reference BE to accurately define the BE scale. In conclusion, the different approaches for the use of reference elements, such as aliphatic carbon, implanted noble gas or surface metals, partially lack practicability and can lead to misinterpretation for application in battery materials. Thus, this manuscript provides exemplary alternative solutions.

This paper reports on a systematic investigation of the ultrashort pulse laser driven acceleration of protons from thin targets of finite size, so-called reduced mass targets (RMTs). Reproducible series of targets, manufactured with lithographic techniques, and varying in size, thickness, and mounting geometry, were irradiated with ultrashort (30 fs) laser pulses of intensities of about 8 × 10 20 W cm −2 . A robust maximum energy enhancement of almost a factor of two was found when comparing gold RMTs to reference irradiations of plain gold foils of the same thickness. Furthermore, a change of the thickness of these targets has less influence on the measured maximum proton energy when compared to standard foils, which, based on detailed particle-in-cell simulations, can be explained by the influence of the RMT geometry on the electron sheath. The performance gain was, however, restricted to lateral target sizes of greater than 50 µm, which can be attributed to edge and mounting structure influences.

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Ordered mesoporous carbide-derived carbon (OM-CDC) with a specific surface area as high as 2900 m(2) g(-1) was used as a model system in a supercapacitor setup based on an ionic liquid (IL; 1-ethyl-3-methylimidazolium tetrafluoroborate) electrolyte. Our study systematically investigates the effect of surface functional groups on IL-based carbon supercapacitors. Oxygen and chlorine functionalization was achieved by air oxidation and chlorine treatment, respectively, to introduce well-defined levels of polarity. The latter was analyzed by means of water physisorption isotherms at 298 K, and the functionalization level was quantified with X-ray photoelectron spectroscopy. While oxygen functionalization leads to a decreased capacitance at higher power densities, surface chlorination significantly improves the rate capability. A high specific capacitance of up to 203 F g(-1) was observed for a chlorinated OM-CDC sample with a drastically increased rate capability in a voltage range of ±3.4 V.

Articles you may be interested inSelf-sensing cantilevers with integrated conductive coaxial tips for high-resolution electrical scanning probe metrology All-diamond cantilever probes for scanning probe microscopy applications realized by a proximity lithography process Rev. Sci. Instrum. 77, 043708 (2006); Scanning proximity probes are uniquely powerful tools for analysis, manipulation, and bottom-up synthesis. A massively parallel cantilever-probe platform is demonstrated. 128 self-sensing and self-actuated proximal probes are discussed. Readout based on piezoresistive sensors and bending control based on bimorph dc/ac actuations are described in detail.

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