Humboldt Fellow joins HZB for battery research
Dr. Wenxi Wang specialises in the design of organic electrodes for lithium-sulfur and zinc-ion batteries and investigates interactions between ions and active materials. © arö/HZB
Dr. Wenxi Wang is working in the team of Prof. Yan Lu as Humboldt Foundation postdoctoral fellow. He studied at the Southern University of Science and Technology in Shenzhen, China, and completed his doctorate at the King Abdullah University of Science and Technology in Saudi Arabia. He specialises in the precise design of organic electrodes for lithium-sulfur and zinc-ion batteries and the investigation of the interactions between ions and active materials.
"At Helmholtz-Zentrum Berlin I find excellent conditions to deepen my research," says Wenxi Wang. Prof. Yan Lu's group has extensive experience in the synthesis and characterisation of novel electrode materials and state-of-the-art infrastructures for battery research. In addition, the X-ray source BESSY II at HZB offers a variety of spectroscopic methods to analyse electrochemical reactions in real time.
Lithium-sulfur (Li-S) batteries are considered one of the most interesting technologies to replace lithium-ion batteries due to their extremely high energy density and cheap starting materials. However, their performance still falls far short of expectations due, in part due to polysulfide intermediates that form during charging cycles. Porous host materials can trap such polysulfides, improving the energy density and lifetime of Li-S batteries. "My research project focuses on the precise design of organic-based host materials with suitable pore sizes and functional groups (Covalent Organic Frameworks, COF) to enable high-performance Li-S batteries and deepen our understanding of their mechanisms," says Wang.
- Battery research: visualisation of aging processes operandoLithium button cells with electrodes made of nickel-manganese-cobalt oxides (NMC) are very powerful. Unfortunately, their capacity decreases over time. Now, for the first time, a team has used a non-destructive method to observe how the elemental composition of the individual layers in a button cell changes during charging cycles. The study, now published in the journal Small, involved teams from the Physikalisch-Technische Bundesanstalt (PTB), the University of Münster, researchers from the SyncLab research group at HZB and the BLiX laboratory at the Technical University of Berlin. Measurements were carried out in the BLiX laboratory and at the BESSY II synchrotron radiation source.
- New instrument at BESSY II: The OÆSE endstation in EMILA new instrument is now available at BESSY II for investigating catalyst materials, battery electrodes and other energy devices under operating conditions: the Operando Absorption and Emission Spectroscopy on EMIL (OÆSE) endstation in the Energy Materials In-situ Laboratory Berlin (EMIL). A team led by Raul Garcia-Diez and Marcus Bär showcases the instrument’s capabilities via a proof-of-concept study on electrodeposited copper.
- Green hydrogen: A cage structured material transforms into a performant catalystClathrates are characterised by a complex cage structure that provides space for guest ions too. Now, for the first time, a team has investigated the suitability of clathrates as catalysts for electrolytic hydrogen production with impressive results: the clathrate sample was even more efficient and robust than currently used nickel-based catalysts. They also found a reason for this enhanced performance. Measurements at BESSY II showed that the clathrates undergo structural changes during the catalytic reaction: the three-dimensional cage structure decays into ultra-thin nanosheets that allow maximum contact with active catalytic centres. The study has been published in the journal ‘Angewandte Chemie’.