The research of the van Wüllen group in Münster – currently one post-doc, two PhD students and one bachelor student – is devoted to inorganic materials research and modern Solid State NMR spectroscopy. Two classes of materials are currently in the focus of our research interest: amorphous inorganic materials (ceramics, glasses) and battery materials for Li batteries.
Ceramics and glasses are found in a wide variety of
industrial applications. The large compositional degree of freedom constitutes
a particularly attractive feature, which allows for a detailed fine-tuning of
the materials’ key properties. Current projects in our group focus on the
synthesis and characterization of melt-derived and sol-gel processed
borosilicate and aluminophosphate glasses for use e.g. as antioxidation
coatings or nuclear waste confinement.
As
for the battery materials, the growing demand for
electric vehicles renders the development of battery systems with
increased
energy densities necessary, entailing an intensive search for new
anode,
cathode and electrolyte materials. Our present interest concentrates on
the
synthesis and characterization of novel solid state electrolyte materials
with
enhanced ionic conductivities for use as solid electrolytes in Li
batteries. Current
projects include the synthesis and characterization of nano-composites
(polymer
electrolytes / Al2O3), novel salt-rich electrolytes employing polymers
with
restricted ability to coordinate Li cations (e.g. Li-salt / PAN) and
hybrid
systems (SiO2 glass / ionic liquid – Li salt).
For a controlled fine-tuning of the materials’ key
properties, such as high temperature stability, ionic conductivity and
mechanical stability, a detailed knowledge of the structural and
dynamic
features of the materials poses a prerequisite. To this end we develop
and
utilize modern Solid State NMR strategies which not only provide
information
about the structural motifs on short and intermediate length scales but
also
offer a handle to study the microscopic dynamics within these
materials. Contributions
to the inventory of modern NMR approaches include the development of
novel
dipolar NMR techniques (e.g. dipolar NMR for nuclei with close
resonance
frequencies, constant time REDOR) and the design of a ultra-high
temperature
MAS NMR probe. Together with information from complementary tools (e.g.
XPS,
Raman, EIS, XRD, …) this enables us to provide detailed information
about the
structure (network models, local cation and anion coordination motifs,
evolution of the structure at high temperatures, host-guest
interactions, …)
and dynamics (hopping sites, migration pathways, activation energies, …
) of
the materials. The knowledge of the microscopic structural and dynamic features may and will then be
used to develop materials with optimized key properties.
Further information about current projects may be obtained following the links below.
| From structure to function: The structure of amorphous solids. |
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 | Cation Transport in Crystalline Ionic Conductors |
 | Searching for novel electrolyte materials with optimzed performance Nano-composites, salt-rich polymer electrolytes, hybrid systems |
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