A5056144599- Fuel Cells and Related Materials
- Electrocatalysts for Energy Conversion
- Advancements in Battery Materials
- Advanced Battery Technologies Research
- Advanced Battery Materials and Technologies
- Hybrid Renewable Energy Systems
- Advanced battery technologies research
- Extraction and Separation Processes
- Electron and X-Ray Spectroscopy Techniques
- Catalytic Processes in Materials Science
- Membrane-based Ion Separation Techniques
- Semiconductor materials and devices
- CO2 Reduction Techniques and Catalysts
- Catalysis and Hydrodesulfurization Studies
- Metalloenzymes and iron-sulfur proteins
- Recycling and Waste Management Techniques
- Advancements in Solid Oxide Fuel Cells
- Supercapacitor Materials and Fabrication
- Conducting polymers and applications
- Catalysis for Biomass Conversion
- Hydrogen Storage and Materials
- Semiconductor materials and interfaces
- Corrosion Behavior and Inhibition
- Chemical Synthesis and Characterization
- Nanomaterials for catalytic reactions
Helmholtz Institute Erlangen-Nürnberg
2021-2025
Friedrich-Alexander-Universität Erlangen-Nürnberg
2021-2025
Forschungszentrum Jülich
2021-2025
Technical University of Munich
2014-2023
Lawrence Berkeley National Laboratory
2017-2019
<italic>Operando</italic> X-ray absorption spectroscopy studies of transition metal dissolution in Li-ion batteries.
Washing is a commonly used method to remove surface impurities of cathode materials for lithium-ion batteries. However, clear mechanistic understanding the washing process missing in literature. In this study, we will investigate effect and subsequent drying nickel-rich NCM cathodes (85% nickel) with respect gassing impedance washed cathodes. By on-line electrochemical mass spectrometry (OEMS), show drastic reduction O2 release above 80% SOC deionized water, suggesting formation an...
Layered lithium transition metal oxides are state-of-the-art cathode materials for Li-ion batteries. Nickel-rich layered suffer from high surface reactivity toward ambient air. Besides hydroxides, carbonates known to be the major impurities formed. While decomposition of Li2CO3 in a battery cell has been studied extensively, mechanistic aspects its during formation/cycling still highly controversial. The reaction standard electrolyte is by on-line electrochemical mass spectrometry, employing...
Ni-rich layered oxides, like NCM-811, are promising lithium-ion battery cathode materials for applications such as electric vehicles. However, pronounced capacity fading, especially at high voltages, still lead to a limited cycle life, whereby the underlying degradation mechanisms, e.g. whether they detrimental reactions in bulk or surface, controversially discussed. Here, we investigate fading of NCM-811/graphite full-cells over 1000 cycles by combination situ synchrotron X-ray powder...
High degrees of delithiation layered transition metal oxide cathode active materials (NCMs and HE-NCM) for lithium-ion batteries (LIBs) was shown to lead the release singlet oxygen, which is accompanied by enhanced electrolyte decomposition. Here, we study reactivity chemically produced oxygen with commonly used cyclic linear carbonate solvents LIB electrolytes. On-line gassing analysis decomposition ethylene (EC) dimethyl (DMC) reveals different stability toward chemical attack in situ...
We use on-line electrochemical mass spectrometry (OEMS) to elucidate and quantify the electrolyte reduction on graphite caused by transition metal ions. To have a controlled system, we ethylene carbonate (EC) with 1.5 M LiPF6 representative amounts of Ni(TFSI)2 or Mn(TFSI)2 as model electrolytes, combined 2-compartment cell in which anolyte catholyte are separated an impermeable solid lithium ion conductor. Focusing C2H4 evolution marker for EC reduction, find that both Ni2+ Mn2+ lead...
Replacement of conventional cars with battery electric vehicles (BEVs) offers an opportunity to significantly reduce future carbon dioxide emissions. One possible way facilitate widespread acceptance BEVs is replace the lithium-ion batteries used in existing a lithium-sulfur battery, which operates using cheap and abundant raw material high specific energy density. These significant theoretical advantages over technology have generated lot interest system, but development practical...
Lowering of the oxygen evolution reaction (OER) noble metal catalyst loading on anode a polymer electrolyte membrane water electrolysis (PEMWE) is necessity for enabling large-scale hydrogen production based this technology. This study introduces remarkably active OER that dispersion Ir nanoparticles highly conductive oxide support. The was designed in way to combine all characteristics have been reported enhance activity an oxide-based catalyst, including high and controlling particle size,...
Significant mass-transport resistances in polymer-electrolyte-fuel-cell catalyst layers (CLs) impose a lower limit on Pt-loading levels, hindering wide-spread fuel-cell commercialization. The origin of this resistance remains unclear. Minimization CL is imperative to achieve better design and performance. In paper, an operando method based H2 limiting current used characterize quantify traditional porous Pt/carbon-based electrodes. sub-resistances are isolated using continuum multiscale...
We report the synthesis of a polystyrene-based anion exchange polymer bearing cationic charge at C6-spacer. The is prepared by functionalized monomer strategy. First, copper halide catalyzed C-C coupling reaction between styryl Grignard and 1,6-dibromohexane applied, followed quaternization with N-methylpiperidine free radical polymerization. novel blended polybenzimidazole O-PBI to yield mechanically stable blend membranes representing new class membranes. In this regard, ratio varied study...
Abstract The widespread application of green hydrogen production technologies requires cost reduction crucial elements. To achieve this, a viable pathway to reduce the iridium loading in proton exchange membrane water electrolysis (PEMWE) is explored. Herein, scalable synthesis method based on photodeposition process for TiO 2 @IrO x core–shell catalyst with reduced content as low 40 wt.% presented. Using this method, titania support particles homogeneously coated thin oxide shell only 2.1 ±...
Lithium-sulfur (Li-S) batteries are facing various challenges with regards to performance and durability, further improvements require a better understanding of the fundamental working mechanisms, including an identification reaction intermediates in operating Li-S battery. In this study, we present operando transmission UV–vis spectro-electrochemical cell design that employs conventional sulfur/carbon composite electrode, propose comprehensive peak assignment for polysulfides DOL:DME-based...
High-temperature proton-exchange membrane fuel cells (HT-PEMFCs) are mostly based on acid-doped membranes composed of polybenzimidazole (PBI). A severe drawback is the deterioration mechanical properties upon increasing acid-doping levels. Cross-linking different polymers a way to mitigate stability issues. In this study, new ion-pair-coordinated (IPM) system with quaternary ammonium groups for application in HT-PEMFCs introduced. PBI cross-linked poly(vinylbenzyl chloride) and quaternized...
Abstract Polymer electrolyte membrane water electrolyzers (PEMWE) are currently restricted to an operating temperature range between 50 80 °C. This review shows that elevated (ET) above 90 °C can be advantageous with respect i) reduced cell voltages, ii) a reduction of catalyst loading or possibly the employment less noble electrocatalysts, and iii) greater potential for waste heat utilization when electrolyzer is operated in exothermal mode (when voltage higher than thermoneutral voltage)....
Abstract In this study we show the possibility to close hydrogen and oxygen mass balance for proton exchange membrane (PEM) water electrolysis cells at lab scale 80°C. By a combined analysis of cathode anode exhaust with respect absolute gas fluxes detected, can quantify true Faradaic efficiency system production. While both exhausts, cathode, contain an apparent flux, there is certain missing share not leaving cell, corresponding roughly 2% ambient pressure operation. This flux shows 2:1...
Abstract Fuel cells play a key role in the energy transition to renewable resources. Many of these systems are based on substrates coated with thin layers containing catalyst, ionomer or support material like carbon. In order experimentally define optimal catalyst layer configuration, one must do step‐by‐step variations its components. Currently this be done several single coating experiments. Here we present tabletop roll‐to‐roll (R2R) slot die setup for producing wet film graded...
The widespread application of green hydrogen production technologies requires cost reduction crucial elements. To achieve this, a viable pathway to reduce the iridium loading in proton exchange membrane water electrolysis (PEMWE) is explored. Herein, we present scalable synthesis method based on photodeposition process for TiO2@IrOx core-shell catalyst with reduced content as low 40 wt%. Using this route, obtain titania support particles homogeneously coated thin oxide shell only 2.1 ± 0.4...
Trimethylboroxine (TMB) is used as an additive in the electrolyte for improving performance of LiCoPO4 (LCP) Li-ion batteries. In this work, role and behavior TMB are investigated by cyclic voltammetry (CV), impedance spectroscopy (EIS) on line electrochemical mass (OEMS). It was found that oxidizes from 4.6 V a low amount necessary to obtain good performance. On one hand, its oxidation produces boron trifluoride (BF3), phosphorylfluoride (POF3) carbanion (CH3‑) linked huge increase...
A new operando spectro-electrochemical setup was developed to study oxygen depletion from the surface of layered transition metal oxide particles at high degrees delithiation. An NCM111 working electrode paired with a chemically delithiated LiFePO4 counter in fuel cell-inspired membrane assembly (MEA). propylene carbonate-soaked Li-ion conducting ionomer served as an electrolyte, providing both good electrochemical performance and direct probing during cycling by ambient pressure X-ray...
Gas crossover is critical in proton exchange membrane (PEM)-based electrochemical systems. Recently, single-layer graphene (SLG) has gained great research interest due to its outstanding properties as a barrier layer for small molecules like hydrogen. However, the applicability of SLG gas-blocking interlayer PEMs yet be fully understood. In this work, two different approaches transferring from copper or polymeric substrate onto are compared regarding their application low-temperature PEM...
The underlying mechanism of lithium-sulfur batteries is still not fully established because it involves a series both chemical and electrochemical reactions as well the formation soluble polysulfide intermediates. To improve mechanistic understanding batteries, this study investigates between Li2S cathode more oxidized sulfur species, such S8 polysulfides, during charge battery. By combining electrochemistry with X-ray absorption spectroscopy, we show that and, in particular, resulting...
Abstract H 2 is a promising fuel for sustainable energy conversion and storage. The development of effective earth abundant evolution catalysts integral to advancing hydrogen‐based technologies. by molecular complexes classically involves the formation metal hydride intermediates. Recently, use redox‐active ligands has emerged as an alternate strategy electron proton Herein, we examine electrocatalytic behavior [Co II (Mabiq)(THF)](PF 6 ) ( Co Mbq ), containing macrocyclic ligand, in acidic,...