Academic Research

This project focuses on developing sustainable alkali-metal batteries based on abundant elements such as sulfur, sodium, and potassium, designed to operate at or near room temperature. The research involves creating semi-solid interlayers to stabilize the anode interface and optimizing sulfur-based cathodes for efficient cycling.
Spectroscopic studies of polysulfide species and systematic solvent screening guide the design of compatible and stable catholytes. Through electrochemical testing, the project aims to establish the key factors governing performance and durability. Ultimately, it seeks to realize a room-temperature potassium–sulfur battery with high energy efficiency and long-term stability.


Context: The transition from fossil fuels to renewable energy demands sustainable and efficient energy storage solutions with high energy and power density. While the lithium-ion technology has advanced electric vehicles and consumer electronics, it has limitations, particularly due to its bulky intercalation anode. Alkali-metal batteries are a promising alternative, since they eliminate the need for intercalation materials in the anode, leading to higher energy density and lower production costs. Moreover, using abundant materials like sulfur, sodium, and potassium enhances sustainability and reduces environmental and supply chain risks compared to lithium and cobalt. However, key challenges must be addressed for these technologies to compete with lithium-ion batteries. Current sodium-sulfur batteries, for example, operate at high temperatures (around 300 °C). Our research focuses on adapting the positive features of these batteries to function at room temperature, making them suitable for applications like electric mobility.

General information: The Graeber Lab for Energy Research (GER) at Humboldt-Universität zu Berlin (HU) combines fundamental studies of micro- and nanoscale interfacial transport processes with the development of novel nanostructured materials to create innovative solutions in energy conversion applications. At GER, we address challenges with a team approach, share our knowledge and skills with each other to create a collaborative, positive atmosphere.

With our work, we aim to enable sustainable alkali-metal batteries based on abundantly available elements such as sulfur, sodium, and potassium. In contrast to commercially available high-temperature sodium–sulfur cells, our goal is to achieve significantly lower operating temperatures, ideally down to room temperature.

The internship focuses on the development of sustainable alkali-metal batteries based on sulfur, sodium, and potassium that operate at near-room temperature. Interns will investigate cathode and anode materials, study the solubility and stability of sulfur and polysulfides, and analyze their interactions using spectroscopic techniques (UV-Vis, Raman). Activities include assembling and testing electrochemical cells, evaluating performance through cycling and impedance measurements, and interpreting experimental data. The position offers hands-on experience in electrochemistry, materials science, and battery research.

Advanced undergraduate students (from third year) 
Master's students 
Ph.D. students 

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