Development of 3D model electrodes with hybrid manufacturing processes (3D-Bat-Hybrid)

• Applicant: Professor Dr. Wilhelm Pfleging
• Subject Area: Synthesis and Properties of Functional Materials
• Term: since 2021
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 467624762

In frame of the project, silicon/graphite (Si/C) anode materials with novel 3D electrode architectures are being developed and evaluated. By combining laser ablation and laser printing (LIFT, laser-induced forward transfer), three-dimensional microstructures and material arrangements are to be represented in model systems with different mass loadings. Using electrochemical methods (cyclic cell tests, galvanostatic intermittent titration technique, electrochemical impedance spectroscopy, cyclic voltammetry) and laser-induced breakdown spectroscopy (LIBS), the electrochemical characteristics are quantified for the new 3D electrode architectures and possible aging phenomena are identified in order to create optimized design concepts for Si/C anode architectures. The influence of the electrode architectures and lithium diffusion pathways realized through a combination of additive and subtractive structuring methods on the electrochemical characteristics is recorded quantitatively and classified in Ragone diagrams with regard to the electrochemical performance.The following scientific goals are being worked on:1. Development of Si/C anodes with Si proportions in the range of 5-50 wt.% for anode layer thicknesses in the range of 30-150 µm2. Correlation of process parameters, microstructure and the resulting electrochemical properties3. Obtaining a basic understanding of the structure-property relationships by classifying the electrochemical characteristics of electrode architectures with regard to achievable energy and power densities (Ragone diagram)4. Transfer of the structure-property relationships to a cell-based battery model (Comsol®) with effective transport parameters (Newman approach "P4D")5. Identification and evaluation of the cell degradation mechanisms (chemical, mechanical) with regard to the influences of material and microstructure characteristics.A laser-based scientific approach was chosen for the project to counteract Si/C anode degradation caused by locally induced mechanical stresses and deformations. This is to be achieved by introducing three-dimensionally arranged active materials (graphite and silicon), embedded in 3D topographies, with a high Si mass proportion. Due to the enlarged active surface of the 3D electrode structure, charge transfer resistance and diffusion overpotential are reduced, which is important for high charge and discharge currents. This new method is helping to develop energy storage materials for lithium-ion batteries with enhanced power, high rate capability, and longer lifetime.

• DFG Programme: Research Grants