• Eschelmüller, Bernd
• Fröhlich, Katja
• Jahn, Marcus

Abstract

Novel technologies and production methods are under development in order to enhance the electrochemical performance of Li-ion battery systems to meet ambitious key requirements, e.g., gravimetric energy densities around 700 Wh/l, improved fast charging capability, and reduced capacity fading to enlarge BEV ranges. Layered oxide cathodes, like nickel manganese cobalt oxides (NMC) might provide a satisfactory suitable solution for future BEV energy storage systems [1]. The attempt to reduce the Co-content with a concurrent increased Ni-content in the mentioned NMC cathodes such as NMC 811 are currently focus of recent studies [2]. It has to be considered that NMC cathodes suffer from low high-rate capability and corresponding low capacity retention at high C-rates. This side effects are monitored in further extend for thick film electrode applications. In order to prevent this, high repetition ultrafast laser ablation is proposed as a most promising and versatile approach. The laser structured 3D electrode surface enhances the liquid electrolyte wettability and reduces cell overpotential at high power operation. Additionally, the lithium-ion transport pathway is reconstructed which leads to improved overall ion diffusion kinetics [3]. The overall approach is to advance the electrochemical performance of batteries using thick film Ni-rich NMC811 cathodes and graphite anodes on different cell configurations, coin cells, single-layer pouch cells, and multi-layer pouch cells, respectively, by using this novel laser pattern technique in combination with NMC811 powder stabilisation. The prime focus is on the scale-up feasibility of the electrode production along with the integrated, continuous roll-to-roll structuring in order to produce next generation NMC batteries with significantly improved performance characteristics. This work was performed under the frame of the RealLi! project, in which the following aspects are covered: Development of thick film NMC811 electrodes with high areal capacity. Passivation approach to improve cycle stability and lifetime. Cell assembly and electrochemical characterization. Holistic evaluation of the potential environmental impact of the NMC811 cells via life cycle assessment. An experimentally validated electrochemical model to describe electrode structures and their optimization. Improved electrochemical performance of NMC811 electrodes on a laboratory scale by using 3D laser structuring. Scale up of the electrode structuring process and corresponding improved electrochemical performance of NMC811 electrodes in pouch cell format by using 3D laser ablation. Holistic performance comparison of the produced cells in different cell configuration levels with and without structured electrodes. Acknowledgments: This work was in the course of project 873396 financially supported by the Austrian Federal Ministry for Climate Action, Environment, Energy, Mobility, Innovation and Technology (bmk). References [1] L. Schweighofer, “Modelling and Optimisation of Laser-Structured Battery Electrodes”, MDPI, Nanomaterials 12(9), 2022 [2] C. of the European Parlament, Tackling the Challenges in commodity markets on raw materials, “Tackling the Challenges in commodity markets on raw materials”, 2011. [3] W. Pfleging, “Recent progress in laser texturing of battery materials: a review of tuning electrochemical performances, related material development, and prospects for large-scale manufacturing”, Int. J. Extrem. Manuf., vol. 3, 2020.

Topics

• impedance spectroscopy
• surface
• nickel
• mobility
• layered
• cobalt
• Lithium
• Manganese
• laser ablation