As the demand for high-performance batteries continues to surge across various applications, researchers are delving into the development of electrochemical energy storage systems, particularly for electromobility. Addressing factors such as charging capacities, speed, life span, safety, raw material availability, and CO2 balance is crucial in advancing materials science. A collaborative effort led by chemists Dr. Hanyu Huo and Prof. Dr. Jürgen Janek (both from Justus Liebig University Giessen) has explored the potential of silicon anodes in solid-state batteries, aiming to improve their overall performance. The findings, focusing on the stability, chemomechanics, and aging behavior of silicon electrodes, have been published in the journal Nature Materials.
The research team employed a combination of experimental and theoretical methods to assess lithium transport in the electrode, the mechanical volume change of silicon during charging and discharging, and its reaction with the solid electrolyte. The study marks a fundamental analysis, representing a significant step towards utilizing silicon as an electrode material in solid-state batteries—an area of intense international research.
Solid-state batteries, an advanced concept compared to lithium-ion batteries, use a solid electrolyte instead of a liquid, organic electrolyte, promising improved storage properties, longer lifespan, and enhanced safety. Prof. Janek, one of the authors, emphasizes the challenges faced during the charging process, where lithium absorption causes significant expansion in the silicon anode, leading to mechanical issues. Additionally, reactions with stored lithium and solid electrolytes contribute to capacity losses.
In the quest for more powerful solid-state batteries to rival conventional lithium-ion batteries, materials with high storage capacities, such as lithium metal, are sought for the anode. However, the associated risks, like internal short circuits, prompt the investigation of alternatives like silicon. The results of the study indicate significant potential for silicon anodes in solid-state batteries, with the possibility of optimization through interface adjustments. The research suggests that additional material concepts, such as polymer interlayers, could play a crucial role in overcoming chemical and chemomechanical aging in silicon anodes.