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Page 40
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
A
ll solid state batteries are expected as the next generation
secondary batteries for their higher energy density,
inflammable properties, and so on. In order to develop these
batteries, there are several problems to improve. One of the
important to improve is the ionic conductivities of the solid
state electrolyte. In order to improve the ionic conductivity,
electronic states of the sulfide based lithium ion conducting
glasses were calculated by the DV-Xα cluster method, which is
one of the first principle density functional methods. The cluster
models were constructed by the coordination number reported
by experimental methods and the bond length estimated from
the ionic radii of each ion. The movement of the Li ion was
simulated by several model clusters with different positions
of the moving ion. The relationship between ionic conductivity
and the differential total bond overlap population (DBOP) of
the moving ion was discussed for the sulfide based glasses
in the systems Li
2
S–SiS
2
–Al
2
S
3
and Li
2
S–SiS
2
–P2S
5
. In these
glasses, the DBOP with the movement of the lithium ion had
good negative correlations with the ionic conductivities and
positive correlations with the activation energies obtained by
the experimental measurements. In any cases, the smaller
change of DBOP of the moving cations played an important
role for the fast ion movement in the superionic conducting
glasses. In order to search for additives with higher ionic
conductivity, the composition dependence of differential total
bond overlap population with addition of various fourth periodic
elements to Li
2
S-SiS
2
solid state electrolyte was estimated, as
shown in the figure. As described above, the smaller change of
the total bond overlap population with the moving Li ion makes
lager ionic conductivities. The figure suggests that the addition
of In, Sn and Sb to Li
2
S-SiS
2
solid state electrolyte could show
larger ionic conductivities. This bonding state of the moving
cations is one of the characteristics of the electronic state in
the sulfide based lithium ion conducting glasses.
Recent Publications
1. Hakari T, Deguchi M, Mitsuhara K, Ohta T, Saito K,
Orikasa Y, Uchimoto Y, Kowada Y, Hayashi A and
Tatsumisago M (2017) Structural and electronic-
state changes of a sulfide solid electrolyte during
the li deinsertion-insertion processes. Chemistry of
Materials 29(11):4768-4774.
2. Matsuyama T, Deguchi M, Mitsuhara K, Ohta T, Mori
T, Orikasa Y, Uchimoto Y, Kowada Y, Hayashi A and
Tatsumisago M (2016) Structure analyses using X-ray
photoelectron spectroscopy and X-ray absorption
near edge structure for amorphous MS3 (M: Ti, Mo)
electrodes in all-solid-state lithium batteries. Journal
of Power Sources 313:104-111.
3. Kowada Y, Hayashi A and Tatsumisago M (2010)
Chemical bonding of li ions in li7p3s11 crystal. Journal
of the Physical Society of Japan 79:65-68.
4. Kowada Y, Tatsumisago M and Minami T (2009)
Chemical bonding and lithium ion conductions in
Li3N. Solid State Ionics 180(6-8):462-466.
5. Kowada K, Nishitani W and Ogasawara K (2009) Total
cluster energy calculation of lithium ion conductors by
the dv-xα method. International Journal of Quantum
Chemistry 109(12):2658-2663.
Biography
Yoshiyuki Kowada has his expertise in structural analysis, electronic state
calculation and chemical bonding analysis of amorphous materials. He ap-
plied the DV-Xα cluster method, which is one of the first principle molecular
orbital calculations to the solid-state electrolytes and phosphor materials
with rare earth ions. Recently, he pays attention on the study about materials
to all solid state Li ion batteries for electric vehicles. He is the President of
the Society for Discrete Variational Xα.
ykowada@hyogo-u.ac.jpElectronic state of sulfide based solid state
electrolytes applied to all solid state lithium ion
secondary batteries
Yoshiyuki Kowada
Hyogo University of Teacher Education, Japan
Yoshiyuki Kowada, Nano Res Appl 2018, Volume 4
DOI: 10.21767/2471-9838-C7-027