Zeitschriftenaufsätze

Der vorgestellte Beitrag beschäftigt sich mit der Untersuchung von geeigneten Bewertungskriterien beim Ultraschallschweißen von Aluminium-Litzen und Kupfer-Kontaktteilen. Der Fokus lag hierbei auf dem Erzeugen verschiedener Kompaktierungszustände durch die Variation der Schweißkraft sowie dessen Auswirkungen auf die Trennkraft und den elektrischen Widerstand. Es konnte gezeigt werden, dass sehr gute Anbindungseigenschaften erzielt werden können, jedoch eine zu geringe bzw. zu starke Kompaktierung nicht geeignet ist. Eine zu geringe Kompaktierung äußert sich in einer unzureichenden Anbindung des Kabels an den Ableiter, während eine zu starke Kompaktierung zum Abtrennen von einzelnen Litzen sowie zu Rissen und dem Bilden von Trennebenen führt. Beides resultiert in verringerten mechanischen und elektrischen Eigenschaften. Somit lassen sich die besten Verbindungeigenschaften für die betrachtete Materialkombination in einem Zwischenbereich (FS = 1170 N - 1340 N) erzielen, was mit den vorgestellten Bewertungskriterien ermittelt werden kann.

LiCoO2 (LCO) is the most successful commercial cathode for lithium-ion batteries due to its high theoretical specific capacity (274 mA h g^-1). However, LCO-based batteries show a significantly high degree of instability in cycling performance and severe capacity fading as voltages exceed 4.35 V versus Li/Li+. Herein, a carbon nanotube macrofilm (CMF) was used as a current collector for addressing the long-standing issues, which demonstrate LCO with the first specific capacities of 191.1 and 180.1 mA h g^-1 after 300 cycles, at 4.5 V. The excellent results are ascribed to the interactions between decomposed electrolytes and carbon nanotubes, which ensure that decomposition products around the cathode are cleaned timely by the current collector cleaner. Therefore an ultrathin cathode electrolyte interphase is obtained and keeps the feature in the subsequent cycles. The assembled LCO-based pouch cell also indicates a high energy density of 523 W h kg^-1 after 200 cycles. This work presents novel insights into cathodes with stable cycling at high voltages.

We provide a review of the latest research findings as well as the future potential of plasma-based etching technology for the fabrication of micro-optical components and systems. Reactive ion etching (RIE) in combination with lithographic patterning is a well-established technology in the field of micro- and nanofabrication. Nevertheless, practical implementation, especially for plasma-based patterning of complex optical materials such as alumino-silicate glasses or glass-ceramics, is still largely based on technological experience rather than established models. Such models require an in-depth understanding of the underlying chemical and physical processes within the plasma and at the glass-plasma/mask-plasma interfaces. We therefore present results that should pave the way for a better understanding of processes and thus for the extension of RIE processes toward innovative three-dimensional (3D) patterning as well as for the processing of chemically and structurally inhomogeneous silicate-based substrates. To this end, we present and discuss the results of a variety of microstructuring strategies for different application areas with a focus on micro-optics. We consider the requirements for refractive and diffractive micro-optical systems and highlight potentials for 3D dry chemical etching by selective tailoring of the material structure. The results thus provide first steps toward a knowledge-based approach to RIE processing of universal dielectric glass materials for optical microsystems, which also has a significant impact on other microscale applications.