Abstracts Book - IMRC 2018

• SC2-O009 Invited Talk
CHARGE STORAGE IN DISORDERED NANOSHEET ELECTRODES:
DEFECTS AND ELECTROCHEMICAL RESPONSES
Scott Misture 1
1 Alfred University, Materials Science, United States.
X-ray total scattering was teamed with X-ray spectroscopy, Raman spectroscopy
and related tools to probe both the mesostructure and the atomic defects of
MnO2-based nanosheet assemblies, revealing a direct link between surface
defects and optical, photochemical and electrochemical function. Of particular
interest is the ability to triple the electrochemical specific capacitance of MnO2
nanostructures by introducing surface Frenkel defects. Beginning with highperfection
microcrystalline KxMnO2 powders, it is possible to exfoliate defectfree
MnO2 nanosheets and subsequently reassemble them into 3-D porous
structures. Controlled reduction of some of the tetravalent Mn leads to tripling
of the electrochemical charge storage capacity. While the effects of defects are
well-understood for bulk solids, we explore the case where the solid is 2-D and
hence “all” surface. As-prepared electrodes are characterized to determine the
overall Mn 3+ defect content and then operando studies highlight the
electrochemical strain induced during cycling. We are able to surmise the
charge storage mechanisms based upon the defect content, Mn charge, and
strain induced during cycling. The results speak to the defects improving charge
transfer resistance and dramatically increasing the specific capacity which might
be applied to similar nanosheet systems as well as 3-D solid surfaces.
Keywords: oxide nanosheet, supercapacitor, defects
Presenting authors email: misture@alfred.edu