A deep understanding of the interaction of the surface of cathode materials with solid electrolytes is crucial to design advanced solid-state batteries (SSBs). This is especially true for the new...

<p>All-solid-state batteries are often expected to replace conventional lithium-ion batteries in the future. However, the practical electrochemical and cycling stability of the best-conducting solid electrolytes, i.e. lithium thiophosphates, are still critical issues that prevent long-term stable high-energy cells. In this study, we use <i>stepwise</i><i>cyclic voltammetry </i>to obtain information on the practical oxidative stability limit of Li₁₀GeP₂S₁₂, a Li₂S‑P₂S₅glass, as well as the argyrodite Li₆PS₅Cl solid electrolytes. We employ indium metal and carbon black as the counter and working electrode, respectively, the latter to increase the interfacial contact area to the electrolyte as compared to the commonly used planar steel electrodes. Using a stepwise increase in the reversal potentials, the onset potential at 25 °C of oxidative decomposition at the electrode-electrolyte interface is identified. X‑ray photoelectron spectroscopy is used to investigate the oxidation of sulfur(-II) in the thiophosphate polyanions to sulfur(0) as the dominant redox process in all electrolytes tested. Our results suggest that after the formation of these decomposition products, significant redox behavior is observed. This explains previously reported redox activity of thiophosphate solid electrolytes, which contributes to the overall cell performance in solid-state batteries. The <i>stepwise cyclic voltammetry</i>approach presented here shows that the practical oxidative stability at 25 °C of thiophosphate solid electrolytes against carbon is kinetically higher than predicted by thermodynamic calculations. The method serves as an efficient guideline for the determination of practical, kinetic stability limits of solid electrolytes. </p>

Structure. -The title thin film electrodes with both a well-defined mesoporous morphology and a nanocrystalline framework are synthesized by a polymer-directed sol-gel route from a mixture of Ti(OBu) 4 , EtOH, AcOH, LiOAc, 2-methoxyethanol, and a poly(ethylene-co-butylene)-block-poly(ethylene oxide) diblock copolymer as the structure-directing agent (dip-coating on polar substrates, 300°C, 12 h). The samples are characterized by SEM, TEM, XPS, impedance spectroscopy, and time-of-flight secondary ion mass spectrometry. The thin film electrodes not only exhibit enhanced lithium storage capabilities at short charging times but also are able to maintain stable cycling performance at rates as high as 64C. Li4Ti5O12 spinel thin films have promise as high rate anode material for thin film microbatteries and hybrid supercapacitor applications. -(HAETGE, J.; HARTMANN, P.; BREZESINSKI, K.; JANEK, J.; BREZESINSKI*, T.; Chem. Mater. 23 (2011) 19, 4384-4393, http://dx.

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