Revealing how formation protocols influence the properties of the solid‐electrolyte interphase (SEI) on Si electrodes is key to developing the next generation of Li‐ion batteries. SEI understanding ...is, however, limited by the low‐throughput nature of conventional characterisation techniques. Herein, correlative scanning electrochemical cell microscopy (SECCM) and shell‐isolated nanoparticles for enhanced Raman spectroscopy (SHINERS) are used for combinatorial screening of the SEI formation under a broad experimental space (20 sets of different conditions with several repeats). This novel approach reveals the heterogeneous nature and dynamics of the SEI electrochemical properties and chemical composition on Si electrodes, which evolve in a characteristic manner as a function of cycle number. Correlative SECCM/SHINERS has the potential to screen thousands of candidate experiments on a variety of battery materials to accelerate the optimization of SEI formation methods, a key bottleneck in battery manufacturing.
Scanning electrochemical cell microscopy (SECCM) enables combinatorial electrochemical assessment of a broad experimental space for solid‐electrolyte interphase (SEI) formation on Si electrodes for Li‐ion batteries, which is correlated to the heterogeneous and dynamic SEI chemistry through co‐located shell‐isolated nanoparticles for enhanced Raman spectroscopy (SHINERS).
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
The study of the OH adsorption process on Pt single crystals is of paramount importance since this adsorbed species is considered the main intermediate in many electrochemical reactions of interest, ...in particular, those oxidation reactions that require a source of oxygen. So far, it is frequently assumed that the OH adsorption on Pt only takes place at potentials higher than 0.55 V (versus the reversible hydrogen electrode), regardless of the Pt surface structure. However, by CO displacement experiments, alternating current voltammetry, and Raman spectroscopy, we demonstrate here that OH is adsorbed at more negative potentials on the low coordinated Pt atoms, the Pt steps. This finding opens a new door in the mechanistic study of many relevant electrochemical reactions, leading to a better understanding that, ultimately, can be essential to reach the final goal of obtaining improved catalysts for electrochemical applications of technological interest.
The addition of tetrabutylammonium (TBA+) to alkaline electrolytes enhances the hydrogen evolution reaction (HER) activity on Pt single-crystal electrodes. The concentration of TBA+ significantly ...influences the HER on Pt(111). Concentrations of ≤1 mM yield no significant effect on HER currents or the coverage of adsorbed hydrogen (H*) but exhibit an interaction with the OHads on the surface. Conversely, concentrations of >1 mM result in an apparent site-blocking effect for underpotential-deposited H* caused by the physisorption of the organic cation, which counterintuitively leads to an increase in the HER activity. The physisorption of TBA+ is linked to its accumulation in the diffuse layer, as it can be reversibly removed by the addition of nonadsorbing cations such as sodium. Following the previous literature on the TBA+ interaction with electrode surfaces, we ascribe this effect to the formation of a two-dimensional TBA+ film in the double layer. On stepped Pt single-crystal surfaces, TBA+ enhances HER activity at all concentrations, primarily at step sites. Our findings not only highlight the complexities of TBA+ accumulation on Pt electrodes but also offer important molecular-level insights for optimizing the HER by organic film formation on various atomic-level electrode structures.
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IJS, KILJ, NUK, PNG, UL, UM
Shell-isolated nanoparticles (SHINs) with a 37 nm gold core and an 11 nm tin dioxide (SnO2) coating exhibited long-life Raman enhancement for 3 months and a wide pH stability of pH 2–13 in comparison ...with conventional SiO2-coated SHINs. Herein, Au–SnO2 is demonstrated as a more durable SHIN for use in the technique Shell-Isolated Nanoparticles for Enhanced Raman Spectroscopy (SHINERS).
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IJS, KILJ, NUK, PNG, UL, UM
The effect of Group 1 alkali-metal cations (Na
+
, K
+
, and Cs
+
) on the oxygen reduction and evolution reactions (ORR and OER) using dimethyl sulfoxide (DMSO)-based electrolytes was investigated. ...Cyclic voltammetry (CV) utilising different Pt-electrode surfaces (polycrystalline Pt, Pt(111) and Pt(100)) was undertaken to investigate the influence of surface structure upon the ORR and OER. For K
+
and Cs
+
, negligible variation in the CV response (in contrast to Na
+
) was observed using Pt(111), Pt(100) and Pt(poly) electrodes, consistent with a weak surface-metal/superoxide complex interaction. Indeed, changes in the half-wave potentials (
E
1/2
) and relative intensities of the redox peaks corresponding to superoxy (O
2
−
) and peroxy (O
2
2−
) ion formation were consistent with a solution-mediated mechanism for larger cations, such as Cs
+
. Support for this finding was obtained
via in situ
shell-isolated nanoparticle-enhanced Raman spectroscopy (SHINERS). During the ORR and in the presence of Cs
+
, O
2
−
and weakly adsorbed caesium superoxide (CsO
2
) species were detected. Because DMSO was found to strongly interact with the surface at potentials associated with the ORR, CsO
2
was readily displaced at more negative potentials
via
increased solvent adsorption at the surface. This finding highlights the important impact of the solvent during ORR/OER reactions.
The effect of Group 1 alkali-metal cations (Na
+
, K
+
, and Cs
+
) on the oxygen reduction and evolution reactions (ORR and OER) using dimethyl sulfoxide (DMSO)-based electrolytes was investigated.
Trace impurities of nitrate and sulphate species have been detected as the cause for the charge quench of existing voltammetric peaks and the appearance of new voltammetric peaks in the blank ...voltammetry of Pt(111) in high-purity perchloric acid. Cyclic voltammetry of Pt(111) in high concentrations of HClO4 (1 M) electrolyte display anomalous reduction peaks at 0.5 and 0.32 VRHE. The reduction of nitrates to nitric oxide, resulting in the reduction peak at 0.32 VRHE, has been detected using in situ Fourier transform infrared spectroscopy. The peak at 0.5 VRHE, previously assigned in the literature to specific adsorption of perchlorate anions catalytically dissociating to chloride anions, is consistent with sulphate desorption as elucidated by spiking HClO4 electrolyte with trace quantities (10 ppm) of sulphuric acid. The presence of kosmotropic sulphate anions was further confirmed by the positive onset potential shift of the sharp OHads butterfly peak at ∼0.8 VRHE with increasing concentrations of HClO4 (0.01–1 M). Although commonly overlooked, we show here the marked deleterious impact these trace impurities have on the blank voltammetry of Pt(111), and provide recommendations for minimising this impact.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Thromboelastometry is considered the best method to assesses hemostasis in liver disease. Diagnostic performance could be improved by adding protein C activators such as thrombomodulin or Protac®. We ...assessed changes in ROTEM parameters after the addition of Protac® in patients with acute-on-chronic liver failure (ACLF), acute decompensation (AD), and healthy individuals (HI) to define different hemostasis patterns, considering standard and velocity ROTEM parameters, and assess whether Protac® can improve the definition of the pattern.
Pre-test, we investigated whether diluted EXTEM reagent improved the effect of Protac® on the clotting time (CT)-ratio with and without Protac®. Ten ACLF and 20 AD patients and 21 HI were included in the main study.
Standard EXTEM was used in the main study. INTEM CFT, INTEM A5 (inverse), and INTEM TPI (inverse) were the parameters that best differentiated liver disease from HI (ROC AUC, 0.921, 0.906, and 0.928, respectively; all P-values < 0.001). Combining INTEM CFT with EXTEM LI60-ratio only slightly improved the diagnostic performance (ROC AUC, 0.948; P < 0.001). EXTEM LI60 and INTEM maxV-t were the parameters that best differentiated between ACLF and AD patients (ROC AUC, 0.743, P = 0.033; and 0.723, P = 0.050; respectively). Combining EXTEM LI60 + INTEM maxV-t moderately improved the diagnostic performance (ROC AUC, 0.81, P < 0.001).
ROTEM velocity, fibrinolysis parameters and the indices calculated improve the diagnosis in combination with standard parameters (e.g., CFT and A5). Ratios calculated with and without Protac® (e.g., EXTEM LI60-ratio) only slightly increased the diagnostic performance in discriminating hemostasis patterns.
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IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
Revealing how formation protocols influence the properties of the solid‐electrolyte interphase (SEI) on Si electrodes is key to developing the next generation of Li‐ion batteries. SEI understanding ...is, however, limited by the low‐throughput nature of conventional characterisation techniques. Herein, correlative scanning electrochemical cell microscopy (SECCM) and shell‐isolated nanoparticles for enhanced Raman spectroscopy (SHINERS) are used for combinatorial screening of the SEI formation under a broad experimental space (20 sets of different conditions with several repeats). This novel approach reveals the heterogeneous nature and dynamics of the SEI electrochemical properties and chemical composition on Si electrodes, which evolve in a characteristic manner as a function of cycle number. Correlative SECCM/SHINERS has the potential to screen thousands of candidate experiments on a variety of battery materials to accelerate the optimization of SEI formation methods, a key bottleneck in battery manufacturing.
Scanning electrochemical cell microscopy (SECCM) enables combinatorial electrochemical assessment of a broad experimental space for solid‐electrolyte interphase (SEI) formation on Si electrodes for Li‐ion batteries, which is correlated to the heterogeneous and dynamic SEI chemistry through co‐located shell‐isolated nanoparticles for enhanced Raman spectroscopy (SHINERS).
Full text
Available for:
BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
