https://hdl.handle.net/10259/5823 2026-04-17T18:47:13Z 2026-04-17T18:47:13Z García, Grecia Dieckhöfer, Stefan Schuhmann, Wolfgang Ventosa Arbaizar, Edgar https://hdl.handle.net/10259/11402 2026-02-19T01:05:49Z 2018-02-01T00:00:00Z

Exceeding 6500 cycles for LiFePO4/Li metal batteries through understanding pulsed charging protocols García, Grecia; Dieckhöfer, Stefan; Schuhmann, Wolfgang; Ventosa Arbaizar, Edgar Improving the performance of Li metal anodes is of key importance for the next generation high energy-density batteries. Here, we study an easily implementable strategy for prolonging the cycle stability of Li metal anodes that is based on the application of pulsed charging protocols. Introducing short periods of relaxation without current flow allows the concentration of Li+ ions to be replenished in front of the electrode surface promoting a uniform and efficient plating of Li metal. We demonstrate that the cycle life of LiFePO4/Li metal batteries is prolonged from 700 to more than 6500 cycles at high charge-rates. In contrast to the assumed failure due to Li dendrite formation, we show that the proposed potential pulse protocols mitigate the growth of a porous film within the Li metal electrode which appears to be responsible for the battery failure.

2018-02-01T00:00:00Z Santos, Carla S. Botz, Alexander Bandarenka, Aliaksandr S. Ventosa Arbaizar, Edgar Schuhmann, Wolfgang https://hdl.handle.net/10259/11382 2026-02-18T01:05:45Z 2022-06-01T00:00:00Z

Correlative Electrochemical Microscopy for the Elucidation of the Local Ionic and Electronic Properties of the Solid Electrolyte Interphase in Li‐Ion Batteries Santos, Carla S.; Botz, Alexander; Bandarenka, Aliaksandr S.; Ventosa Arbaizar, Edgar; Schuhmann, Wolfgang 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. The SEI acts as an insulating layer for electron transfer, still allowing the ionic flux through the layer. 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). Correlations between the electronic and ionic properties of the resulting SEI on a model Cu electrode demonstrates the unique feasibility of the proposed strategy to provide the two essential properties of an SEI: ionic and electronic conductivity in dependence on the formation conditions, which is anticipated to exhibit a significant impact on the field of LIBs.

2022-06-01T00:00:00Z García, Grecia Ventosa Arbaizar, Edgar Schuhmann, Wolfgang https://hdl.handle.net/10259/11378 2026-02-18T01:05:44Z 2017-05-01T00:00:00Z

Complete Prevention of Dendrite Formation in Zn Metal Anodes by Means of Pulsed Charging Protocols García, Grecia; Ventosa Arbaizar, Edgar; Schuhmann, Wolfgang Zn metal as anode in rechargeable batteries, such as Zn/air or Zn/Ni, suffers from poor cyclability. The formation of Zn dendrites upon cycling is the key limiting step. We report a systematic study of the influence of pulsed electroplating protocols on the formation of Zn dendrites and in turn on strategies to completely prevent Zn dendrite formation. Because of the large number of variables in electroplating protocols, a scanning droplet cell technique was adapted as a high-throughput methodology in which a descriptor of the surface roughness can be in situ derived by means of electrochemical impedance spectroscopy. Upon optimizing the electroplating protocol by controlling nucleation, zincate ion depletion, and zincate ion diffusion, scanning electron microscopy and atomic force microscopy confirmed the growth of uniform and homogenous Zn deposits with a complete prevention of dendrite growth. The implementation of pulsed electroplating as the charging protocol for commercially available Ni–Zn batteries leads to substantially prolonged cyclability demonstrating the benefits of pulsed charging in Zn metal-based batteries.

2017-05-01T00:00:00Z Ventosa Arbaizar, Edgar Madej, Edyta Zampardi, Giorgia Mei, Bastian Weide, Philipp Antoni, Hendrik La Mantia, Fabio Muhler, Martin Schuhmann, Wolfgang https://hdl.handle.net/10259/11377 2026-02-18T01:05:43Z 2016-12-01T00:00:00Z

Solid Electrolyte Interphase (SEI) at TiO2 Electrodes in Li-Ion Batteries: Defining Apparent and Effective SEI Based on Evidence from X-ray Photoemission Spectroscopy and Scanning Electrochemical Microscopy Ventosa Arbaizar, Edgar; Madej, Edyta; Zampardi, Giorgia; Mei, Bastian; Weide, Philipp; Antoni, Hendrik; La Mantia, Fabio; Muhler, Martin; Schuhmann, Wolfgang The high (de)lithiation potential of TiO2 (ca. 1.7 V vs Li/Li+ in 1 M Li+) decreases the voltage and, thus, the energy density of a corresponding Li-ion battery. On the other hand, it offers several advantages such as the (de)lithiation potential far from lithium deposition or absence of a solid electrolyte interphase (SEI). The latter is currently under controversial debate as several studies reported the presence of a SEI when operating TiO2 electrodes at potentials above 1.0 V vs Li/Li+. We investigate the formation of a SEI at anatase TiO2 electrodes by means of X-ray photoemission spectroscopy (XPS) and scanning electrochemical microscopy (SECM). The investigations were performed in different potential ranges, namely, during storage (without external polarization), between 3.0–2.0 V and 3.0–1.0 V vs Li/Li+, respectively. No SEI is formed when a completely dried and residues-free TiO2 electrode is cycled between 3.0 and 2.0 V vs Li/Li+. A SEI is detected by XPS in the case of samples stored for 6 weeks or cycled between 3.0 and 1.0 V vs Li/Li+. With use of SECM, it is verified that this SEI does not possess the electrically insulating character as expected for a “classic” SEI. Therefore, we propose the term apparent SEI for TiO2 electrodes to differentiate it from the protecting and effective SEI formed at graphite electrodes.

2016-12-01T00:00:00Z