• Correlative Electrochemical Microscopy for the Elucidation of the Local Ionic and Electronic Properties of the Solid Electrolyte Interphase in Li-ion Batteries

    Carla S. Santos, Alexander Botz, Aliaksandr S. Bandarenka, Edgar Ventosa, Wolfgang Schuhmann
    The solid-electrolyte interphase (SEI) plays a key role in the stability of lithium-ion batteries as the SEI prevents the continuous degradation of the electrolyte at the anode. We combine the feedback and multi-frequency alternating-current modes of scanning electrochemical microscopy (SECM) for the first time to assess quantitatively the local electronic and ionic properties of the SEI varying the SEI formation conditions and the used electrolytes in the field of Li-ion batteries (LIB).
  • Process-Product Interdependencies in Lamination of Electrodes and Separators for Lithium-Ion Batteries

    Ruben Leithoff, Arian Fröhlich, Steffen Masuch, Gabriela Ventura Silva, Klaus Dröder
    In today’s cell production, the focus lies on maximizing productivity while maintaining product quality. To achieve this, the lamination of electrode and separator is one key process technology, as it bonds the electrode and separator to form mechanically resilient intermediate products.This paper addresses the investigation of interdependencies and proposes three characterization methods (grey scale analysis, high potential tests, electrochemical cycling and C-rate tests).
  • Advanced Electrochemical Impedance Spectroscopy of Industrial Ni-Cd Batteries

    Nawfal Al-Zubaidi R-Smith, Manuel Kaspar, Peeyush Kumar, Daniel Nilsson, Björn Marlid, Ferry Kienbarger
    Advanced EIS was applied to characterize industrial Ni-Cd batteries and to investigate the electrochemical redox processes. A two-term calibration workflow was used for accurate complex impedance measurements across a broad frequency range of 10 mHz to 2 kHz, resulting in calibrated resistance and reactance values. The EIS calibration significantly improved the measurements, particularly at high frequencies above 200 Hz, with differences of 6–8% to the uncalibrated impedance.
  • Electrochemical impedance spectroscopy error analysis and round robin on dummy cells and lithium-ion-batteries

    Manuel Kaspar, Arnd Leike, Johannes Thielmann, Christian Winkler, Nawfal Al-Zubaidi R-Smith, Ferry Kienberger
    An interlaboratory Round-Robin comparison between three-labs is conducted where calibrated electrochemical-impedance-spectroscopy (EIS) is measured on prismatic cell dummies and prismatic batteries. Advanced EIS calibration workflow is employed allowing for precise measurements of low micro-Ohm impedances in a broad frequency range of 50 mHz to 10 kHz. Significant systematic-error corrections are obtained from the calibration.
  • New Technique for Probing the Protecting Character of the Solid Electrolyte Interphase as a Critical but Elusive Property for Pursuing Long Cycle Life Lithium-Ion Batteries

    Enrique Garcia-Quismondo, Sandra Alvarez-Conde, Guzmán Garcia, Jesús I. Medina-Santos, Jesús Palma, and Edgar Ventosa
    In this work, a new, cheap and easily-implementable methodology to analyzes the quality of the Solid Electrolyte Interphase (SEI) on the negative electrode of Li-ion batteries (LIBs) is proposed. First, a redox-mediator is added in the electrolyte after the SEI formation cycle, and the redox mediator leads to an internal self-discharge process that is inversely proportional to the electrically-insulating character of the SEI. Second, a few charge and discharge cycles are applied to the battery and the presence of the redox-mediator provokes a shuttle effect enables by the lack of electrically protecting character of the SEI which consumes charges decreasing the coulombic efficiencies, enhancing the sensibility to the SEI protecting nature. We believe that the findings based on the application of this mediator-enhanced coulometry can be used to accurately predict the cyclic behavior of LIBs under extended operating conditions, which is especially relevant for a better comprehension of future industrial needs for battery R&D in cell components and production fields.