Research Topics
Materials chemistry/solid state
electrochemistry of metal oxides, metal phosphates, and pnictides; mesoporous metal
oxides
Ø One of the most
interesting aspects of materials chemistry is the design of structures with
specific physical properties. Using these principles, we construct new
materials, determine their structures and investigate the resultant properties of
the material. We are, in particular, interested in ionic and electronic
transport in materials since these properties can be applied to the development
of specific devices.
Ø The design of advanced materials
for rechargeable lithium or lithium-ion batteries also involves the synthesis
and study of new metal oxide materials. In addition to the development of
"soft" and "hard" solid state synthetic techniques, these
studies involve the investigation of Li ion insertion into the framework using
solid state electrochemical methods, in conjunction with in-situ probes such as
solid state NMR and X-ray diffraction, and ex-situ probes such as X-ray
absorption spectroscopy. We aim at both the preparation of novel
materials, and developing an understanding of the thermodynamics and kinetics
of Li insertion in the materials.
Ø Another area of our
research is focused on developing crystalline metal oxide lattices that possess
more open-framework structures. These lattices are designed to have pores on
the order of 5-40Å. The idea here is to use an organic (or inorganic) molecule
as a "template" around which to grow the inorganic lattice. The shape
of the template is often reflected in the structure of the inorganic framework.
The template molecules can then be removed from the pores, and this allows us
to investigate the electrochemical or catalytic properties of the resultant
framework structure. One of the primary aims is to prepare new structures that
have enhanced electronic/ionic conductivity. The template molecules can also be
designed to form an integral part of the framework to exploit special
properties of the molecule, i.e., conductive polymers or molecules with
fascinating optical properties. Recent work in our group in this area has
generated novel lattice structures including main group phosphates, and
transition metal oxides.
Ø Central to all of our
studies is a range of sophisticated physical measurements carried out in our
lab, and in collaboration with others in the department as part of a
collaborative research team. The techniques include x-ray and neutron
diffraction/scattering, transmission electron microscopy (with Prof. Corbett,
Physics), electrochemical measurements, thermal analysis, and electronic
conductivity measurements. A particularly important tool in our research is
multinuclear solid state NMR (with Prof. Power, Chemistry). This is used to
provide information ranging from polymer conformation, inorganic lattice
structure, to Li+ diffusion rates (7Li NMR). These
methods yield information of the structure-property relationships in the new
materials emerging from our research.