Stabilization of the Si(553) surface by Au adsorption results in two different atomically defined chain types, one of Au atoms and one of Si. At low temperature these chains develop two- and threefold periodicity, respectively, previously attributed to Peierls instabilities. Here we report evidence from scanning tunneling microscopy that rules out this interpretation. The $\ifmmode\times\else\texttimes\fi{}3$ superstructure of the Si chains vanishes for low tunneling bias, i.e., close the Fermi level. In addition, the Au chains remain metallic despite their period doubling. Both observations are inconsistent with a Peierls mechanism. On the contrary, our results are in excellent, detailed agreement with the Si(553)-Au ground state predicted by density-functional theory, where the $\ifmmode\times\else\texttimes\fi{}2$ periodicity of the Au chain is an inherent structural feature and every third Si atom is spin polarized.

Including a certain amount of carbon in the negative active material is currently the state‐of‐the‐art method to improve the dynamic charge acceptance (DCA) of lead–acid batteries. The DCA is a key parameter of batteries used in microhybrid cars where brake energy recuperation is implemented. To find the optimal carbon additive, it is essential to test the carbon both in short‐term and long‐term tests. This work investigates the long‐term and short‐term DCA of 2 V, 2.5 Ah lead–acid cells and correlates the results with the external surface area of the carbon. Five different carbons with tailored particle size (27–633 nm) and external surface area (7.1–159.3 m² g⁻¹) are employed as additives in the negative electrodes. The charge acceptance of cells according to the charge acceptance test 2 (SBA), the DCA (EN) test, and the run‐in DCA test (Ford) is increased via an increase in the carbon external surface area. A correlation between the short‐term tests and the first week of the run‐in DCA test is established for the carbon impact. After several weeks of run‐in DCA test, the carbon effect is diminished and only a differentiation between high and low DCA cells is possible.

The subject of this study is test cells extracted from industrially manufactured automotive batteries. Each test cell either had a full set of plates or a reduced, negative-limited set of plates. With these test cells the predictability of the dynamic charge acceptance (DCA) by using electrochemical impedance spectroscopy (EIS) is investigated. Thereby, the DCA was performed according to EN 50342-6:2015 standard. The micro cycling approach was used for the EIS measurements to disregard any influencing factors from previous usage. During the evaluation, Kramers-Kronig (K-K) was used to avoid systematic errors caused by violations of the stationarity, time-invariance or linearity. Furthermore, the analysis of the distribution of relaxation times (DRT) was used to identify a usable equivalent circuit model (ECM) and starting values for the parameter prediction. For all cell types and layouts, the resistance R₁, the parameter indicating the size of the first/high-frequency semicircle, is smaller for cells with higher DCA. According to the literature, this semicircle represents the charge transfer reaction, thus confirming that current-enhancing additives may decrease the pore diameter of the negative electrode.