05 Fakultät Informatik, Elektrotechnik und Informationstechnik

Permanent URI for this collectionhttps://elib.uni-stuttgart.de/handle/11682/6

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Institute: search.filters.UBSInstitut.Institut für PhotovoltaikInstitute: search.filters.UBSInstitut.Fakultätsübergreifend / Sonstige EinrichtungStart date: 2020Author: search.filters.author.Biro, DanielSubject: search.filters.subject.540

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    Revealing the local pH value changes of acidic aqueous zinc ion batteries with a manganese dioxide electrode during cycling
    (2020) Bischoff, Christian Friedrich; Fitz, Oliver Sebastian; Burns, Jordan; Bauer, Manuel; Gentischer, Harald; Birke, Kai Peter; Henning, Hans-Martin; Biro, Daniel
    The research on aqueous zinc ion batteries (AZIB) is getting more attention as the energy transition continues to develop and the need for inexpensive and safe stationary storage batteries is growing. As the detailed reaction mechanisms are not conclusively revealed, we want to take an alternative approach to investigate the importance of pH value changes during cycling. By adding a pH-indicator to the electrolyte (2 M ZnSO4 + 0.1 M MnSO4), the local pH-value change during operation is visualized in operando. The overall pH value was found to increase during cycling whereas a major temporary pH drop in close proximity of the manganese dioxide electrode surface occurs. Additionally, this pH value change was quantified locally by in operando measurements with a pH micro electrode. Different electrolyte compositions with additives (sodium dodecyl sulfate (SDS), sulfuric acid (H2SO4)) and operation voltages were tested. The pH-potential-diagrams of manganese and zinc reveal pH value and potential limits, leading to active material dissolution at lower pH values and oxygen gas evolution at higher potentials >1.7 V. The procedure of combining a pH indicator, pH microelectrode measurements and pH-potential diagrams can be seen as an appropriate method to determine the recommendable working window of aqueous batteries.
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    Towards sustainable sulfide‐based all‐solid‐state‐batteries : an experimental investigation of the challenges and opportunities using solid electrolyte free silicon anodes
    (2024) Neumann, Tobias; Alexander Dold, Lukas; Thomas Cerny, Alain; Tröster, Eric; Günthel, Michael; Fischer, Anna; Peter Birke, Kai; Krossing, Ingo; Biro, Daniel
    Silicon is one of the most promising anode active materials for future high–energy lithium‐ion‐batteries (LIB). Due to limitations related to volume changes during de-/lithiation, implementation of this material in commonly used liquid electrolyte‐based LIB needs to be accompanied by material enhancement strategies such as particle structure engineering. In this work, we showcase the possibility to utilize pure silicon as anode active material in a sulfide electrolyte‐based all‐solid‐state battery (ASSB) using a thin separator layer and LiNi0.6Mn0.2Co0.2O2 cathode. We investigate the integration of both solid electrolyte blended anodes and solid electrolyte free anodes and explore the usage of non‐toxic and economically viable solvents suitable for standard atmospheric conditions for the latter. To give an insight into the microstructural changes as well as the lithiation path inside the anode soft X‐ray emission and X‐ray photoelectron spectroscopy were performed after the initial lithiation. Using standard electrochemical analysis methods like galvanostatic cycling and impedance spectroscopy, we demonstrate that both anode types exhibit commendable performance as structural distinctions between two‐dimensional and three‐dimensional interfaces became evident only at high charge rates (8 C).