Myth and Reality of a Universal Lithium-Ion Battery Electrode Design Optimum: A Perspective and Case Study

Abstract

The quest toward optimal electrode design for energy- and power-demanding applications involves besides experimental effort also less resource-intensive model-based studies. The diversity of optimization objectives and benchmark systems complicates the practical utilization of available methods and gained knowledge. Despite the increasing importance of fast charging, electrode design studies commonly focus only on discharge characteristics. This paper features, besides an overview and perspective of electrode structuring concepts and optimization pathways, a model-based full cell parameter screening of two-layered electrodes for charge and discharge. The small fraction of cells with superior performance among the evaluated configurations underlines the importance of a joint experimental and model-based electrode design optimization. The results further indicate that the performance of cell designs tailored for fast charge or fast discharge differs substantially; the gap widens if charging is terminated below 0 V versus Li/Li+ to prevent lithium plating. The broad parameter screening is complemented by a high-resolution half cell parameter study. Their comparison underlines that the benefit of electrode structuring depends heavily on the study extent and the chosen benchmark. Furthermore, the importance of the parameter space surrounding an optimal electrode design for production with process tolerances is highlighted.