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Highly
efficient 3V cathodes for rechargeable sodium-ion batteries have been
developed by researchers from Argonne National Laboratory’s Materials
Science, Chemical Sciences & Engineering, and X-ray Sciences
Divisions, as well as the University of Chicago, together with the
Center for Nanoscale Materials’ NanoBio Interfaces Group. With a
near-theoretical capacity of 250 mAh/g, excellent rate capability and
cycle life, and high energy and power densities of 760 Wh/kg and 1200
W/kg, respectively, these bilayered V2O5 systems can be used in
applications at ambient temperature.
Rechargeable
battery systems with transport ions other than lithium offer an
alternative to lithium-ion batteries that would substantially expand the
existing energy storage market, which is primarily based on lithium-ion
technology. Sodium-based batteries are particularly attractive: Sodium
is a cheap, nontoxic, and abundant element that is uniformly distributed
around the world and therefore would be ideal as a transport ion for
rechargeable batteries.
This
research team’s approach to achieving sodium ion intercalation was to
use nanoscale materials that have two-dimensional layered structures
with adjustable interlayer spacings capable of accommodating large
volume changes. Ex situ and in situ synchrotron characterization studies
revealed that sodium ion uptake induces organization of the overall
vanadia structure together with appearance of long-range order between
the layers. Upon deintercalation of sodium, the long-range order is lost
while the intralayer structure is still preserved. Inducing ordering of
nanomaterials in operando has thus allowed the realization of the
highest possible electrode capacity by optimizing the balance of
electrostatic forces.
Improved
elasticity and exceptional long-term stability of this open framework
structure makes bilayered V2O5 a suitable cathode material for
high-energy density rechargeable sodium batteries.
Nanostructured Bilayered Vanadium Oxide Electrodes for Rechargeable Sodium-Ion Batteries
