22 / 31
Page 75
Volume 4
December 10-12, 2018
Rome, Italy
Nano Research & Applications
ISSN: 2471-9838
Advanced Materials 2018
Nano Engineering 2018
JOINT EVENT
22
nd
International Conference on
Advanced Materials
and Simulation
&
22
nd
Edition of International Conference on
Nano Engineering &
Technology
E
lectrochemical storage of energy through Li ion devices is
the commonly used solution to address the intermittent
character of renewable energy and the increasing demand of
nomad technologies. LiCoO
2
is the most widely used positive
electrode material of today’s Li ion batteries. In the last decade,
much research has been performed to explore alternative
materials as mixed transition metal oxides LiNi
x
Mn
x
Co
1
−
2x
O
2
(NMC). The surface reactivity of these electrode materials
towards the electrolyte is a key feature that has deep impact
on the performance and lifetime of Li-ion cells and need to be
understood and controlled. Within this framework, based on our
previous experience on lithium layered oxides, we decided to
study the surface reactivity of Li
2
MnO
3
which can be viewed as a
model compound for Mn(IV) layered oxides such as NMC or even
Li rich materials. The strategy consists coupling adsorption of
gaseous probe molecule (SO
2
), X-ray photoelectron spectroscopy
(XPS) and DFT calculation in order to identify the influence of the
oxidation state of the transition metal on the adsorption reaction
type (basic/acidic or redox). We focus our study on strengthening
the experimental calculation coupling by studying the reactivity on
a single crystal surface of Li
2
MnO
3
. Both approaches conclude to
a redox adsorption mode with the formation of sulphate species.
Chemical maps of the crystal surface after adsorption obtained
by Auger spectroscopy provide information on the adsorption
sites location. Stacking faults and spinel type default are usually
encountered in the Li
2
MnO
3
crystals. Thus, we completed this
study with the investigation of the surface reactivity of Li
2
MnO
3
polycrystals against the stacking faults rate. Moreover, the
reactivity of Li
1+x
Mn
2
-
x
O
4
spinel materials will be checked to
determine the influence of the spinel type default on the surface
reactivity.
germain.vallverdu@univ-pau.frGermain Vallverdu
1
, Ambroise Quesne-Turin
1
, Delphine Flahaut1, Isabelle Bara-
ille
1
, Laurence Croguennec
2
and
Michel Ménétrié
2
1
University of Pau and Pays de l’Adour, France
Nano Res Appl 2018, Volume 4
DOI: 10.21767/2471-9838-C7-028
Surface reactivity of layered manganese
oxides: an experimental and theoretical
approach