Research Group Helge Stein

Bespoke formation of Batteries offers improved lifetime and performance but is generally associated with long processing times, high cost, and large floorspace. Facile strategies like heating or increasing the formation current, as well as current alterations during formation have their limits in speed up and efficiency. We present pulsed formation on graphitic anode full cells as an accelerated formation strategy and investigate its influence on various quality parameters. Optimized pulsed charging is demonstrated herein to reduce the formation time by more than 50% whilst maintaining or improving all other cell quality parameters including discharge capacity. The newly discovered protocol is scaled up to 25Ah prismatic cells in the PHEV1 format that confirm the accelerated and improved pulsed formation strategy. We attribute the accelerated and improved formation to an apt balance of surface and bulk diffusion which results in thinner, more homogenous SEI. Dynamics of pulsed formation also allow for the extraction of new quality markers while formation is happening.

High-performance batteries need accelerated discovery and optimization of new anode materials. Herein, we explore the Si─Ge─Sn ternary alloy system as a candidate fast-charging anode materials system by utilizing a scanning droplet cell (SDC) as an autonomous electrochemical characterization tool with the goal of subsequent upscaling. As the SDC is performing experiments sequentially, an exploration of the entire ternary space is unfeasible due to time constraints. Thus, closed-loop optimization, guided by real-time data analysis and sequential learning algorithms, is utilized to direct experiments. The lead material identified is scaled up to a coin cell to validate the findings from the autonomous millimeter-scale thin-film electrochemical experimentation. Explainable machine learning (ML) models incorporating data from high-throughput Raman spectroscopy and X-ray diffraction (XRD) are used to elucidate the effect of short and long-range ordering on material performance.