Science on Interfacial Ion Dynamics for Solid State Ionics Devices

Newsletter Vol.3
March 2021

Interface lonics toward
Sustainable Society
2019 – 2023 Japan Society for the Promotion of Science
Grant-in-Aid for Scientific Research on Innovative Areas

2

Preface | Contents

Preface
The COVID-19 global pandemic has restricted various activities. Although
the 1st international conference on “Interface Ionics” was postponed, theutilization of ICT as well as collaborative research and discussions haveprogressed more rapidly than originally planned. We are optimistic that the
pandemic will end soon, but we will continue “Interface Ionics” by effective
management utilizing virtual platforms, online meetings, on-demand video
presentations, etc.
I hope that you and your family keep good health now and in the future.
Yasutoshi Iriyama, Principal Investigator
Nagoya University

Contents

Member Introductions
		 Postdoctoral Researchers

3

Research Achievements
		 Model Interface (Gp-A01)
Advanced Analysis (Gp-A02)

5
6

		 Computational & Data Science (Gp-A03)

7

Design of Functional Interface (Gp-A04)

8

Activity Reports
		 Conferences partially Supported
		 by the “Interface Ionics” Project9

Symposiums and Seminars

10Member Introductions 3

Member Introductions
Postdoctoral Researchers
Gp-A03Hong-Kang Tian
NIMS (Tateyama Gr.)/Multi-scale simulations for all-solid-state batteries

I grew up in Taiwan. I received my Ph.D. in Chemical Engineering from
Michigan State University under the supervision of Professor Yue Qi.
My research focuses on applying multi-scale simulation techniques,
including continuum modeling (Finite Element Analysis) and first-principles
calculations (Density Functional Theory), to investigate interfacial issues.
Specifically, my studies explore contact area loss, stress induced atinterfaces, and the mechanism of Li dendrite growth in the pores andgrain boundaries. In the “Interface Ionics” project, I work to reveal how
Li ions and electrons are transferred across the interface between the
LATP solid electrolyte and the LiCoO2 electrode. In collaboration with
Prof. Muto and Prof. Iriyama, our proposed mechanisms well explain theexperimental observations in different conditions, including before/after
annealing and upon charging. I appreciate this opportunity to participate inthis project and collaborate with talented researchers in experimental andcomputational research groups. I look forward to developing more exciting
stories regarding the interfaces in all-solid-state batteries.

Figure. Li-ion and electron transfer at the LATP/LCO
interface under different conditions.
Adapted with permission from “H.K. Tian, S. Muto, Y.
Iriyama, Y. Tateyama et al., ACS Appl. Mater. Interfaces
12, 54752–54762 (2020)”, the American Chemical
Society.

Gp-A03Magnus So
Kyushu Univ. (Inoue Gr.)
/Numerical simulations

My research is focused on simulating the effects of structural andmechanical properties on the durability and performance of all-solidstate batteries (ASSBs). I mainly focus on particle-based methods suchas the Discrete Element Method (DEM) to investigate contact dynamics
at interfaces and between particles. Recently, we simulated cold press
fabrication and charge expansion in a sulfide ASSB electrode via DEM.
We developed a new cohesive particle model that can simulate bothparticle consolidation during fabrication and material failure during charge
expansion. A high pressure during fabrication induces plastic deformationand the build-up of cohesive contact between particles, which consistof a Si active material (AM) and sulfide solid electrolyte (SE). When AM
expands during charging, it causes delamination and cracking, leading tosubstantional performance losses. In the future, I hope my research can beused to better understand the mechanical interactions between particles
and interfaces toward the development of more durable ASSBs.

Figure. Simulation results of SE (colored) and AM(black) particles.

4

Member Introductions

Gp-A04Benoît Denis Louis Campéon
Yokohama National Univ. (Yabuuchi Gr.)
/Graphene, Electrochemistry

Since early 2016, I have been involved in research related to theelectrochemical synthesis and functionalization of graphene materials forenergy storage devices. During my doctoral thesis initiated in 2017, I
developed an original non-destructive electrochemical synthesis method
for graphene oxide, which eases, speeds up, and reduces the cost of its
production. Following this work, I developed sophisticated methods, whichallow tuning of the graphene oxide chemistry and morphology toward
high performance lithium and sodium ion batteries. In October 2020, I
started working in Prof. Yabuuchi’s group at Yokohama National University.
Currently, I am investigating the development of graphene-based allsolid-state batteries (ASSBs). My initial research aims to design andoptimize the evaluation of a reference ASSB composed of LiFePO4 with apolymer electolyte. The preliminary cell evaluation conducted within a cold
isostatic pressing (CIP) device (Fig. 1) allows the positive effect of pressure
on ASSB interfacial resistances to be precisely studied (Fig. 2).

Figure 1. A digital image of the CIP device connected toa battery test unit.

Figure 2. In-situ CIP Nyquist plots of ASSB at (i) ambientconditions and (ii) 10 MPa.

Gp-A04

Rajendra Hongahally Basappa
Yokohama National Univ. (Yabuuchi Gr.)
/All-solid-state batteries
Since 2014, I have been working on solid electrolytes for all-solid-statebatteries (ASSBs). My doctoral research focused on a garnet-type solid
electrolyte, which offers unprecedented safety and durability to enable theuse of Li metal anodes in ASSBs. Prior to my doctoral research, I worked on
developing tin anode materials for lithium-ion battery applications in India.
My ongoing research activities are focused on a solvent-free hybrid
solid electrolyte (HSE) system such as the integration of lithiumconducting ceramic electrolytes in a polymer matrix, which shows highionic conductivity, and excellent mechanical and thermal properties for
ASSB applications. Recently, to evaluate the full potential of our ASSB,
electrochemical cells were prepared with a polymer membrane. This cell
was assembled with a polymer membrane and electrode material. Cold
isostatic pressing (CIP) effectively reduced the impedance of ASSB. Figure
1 shows a picture of the CIP device. Figure 2 shows the preliminary
result, which demonstrates the advantage of CIP. After CIP treatment, theimpedane of the all-solid-state battery is drastically reduced.

Figure 1. Picture of a cold isostatic pressing (CIP) device.

Figure 2. Nyquist plots of electrochemical cells before
and after CIP.

Research Achievements 5

Research Achievements
2020.7– 2020.12

Gp-A01 Model Interface
Notable research progress includes the preparationof thin film materials and a model of solid electrolytes.
These are useful for analyzing the electrode-solid
electrolyte interface. From the viewpoint of suppressing
side reactions during the interface formation process,several unique processes related to low-temperatureinterface formation and low-temperature material
synthesis have been achieved. In addition, mechanisms
for side reactions and regulating methods duringhigh-temperature sintering or thin-film formation onheated substrates have been proposed. Collaborative
projects with Gp-A02 and Gp-A03 are underway, andinclude examples such as the provision of a model
for all-solid-state batteries and single crystalline solid
electrolytes, and elucidation of the reaction mechanism
ocurring at negative electrodes of (Li, Si, carbon)-solid
electrolyte interfaces.

Highlight 1

High-rate capability of LiCoO2 cathodes
K. Kawashima, T. Ohnishi, K. Takada.
ACS Appl. Energy Mater. vol. 3, pp. 11803–11810 (2020)
Abstract
High-quality (104)-oriented LiCoO2 epitaxial thin film cathodes
exhibit an extremely large high-rate discharge exceeding 100,000
C and 100 mA cm-2 without any capacity loss. A comparison withc-axis oriented epitaxial cathodes indicates a definite anisotropic
rate capability in the layered rock-salt-type LiCoO2. ALCA-SPRING
collaborating work [Reproduced with permission of the American
Chemical Society.]

Highlight 2Synthesis of the metastable cubic phase of Li2OHCl by a Mechanochemical
methodT. Yamamoto, H. Shiba, N. Mitsukuchi, M. K. Sugumar, M. Motoyama, Y. Iriyama.
Inorg. Chem. vol. 59, pp. 11901–11904 (2020)
Abstract
A ductile oxide-based solid electrolyte, Li2OHCl, is prepared atroom temperature by a mechanochemical method. Li2HOCl generally
forms a low-conductive orthorhombic phase at 25 °C, but theas-prepared Li2OHCl forms a cubic Pm3 m structure and shows an–6–1ionic conductivity of 2.6 × 10 S cm at 25 °C. Upon heating the
cubic phase to 200 °C, the orthorhombic Pmc21 structure appears at
25 °C and the ionic conductivity decreases to 1.4 × 10 –7 S cm –1. The
formation of the metastable cubic phase can be explained in termsof the low crystallinity of Li2OHCl derived from mechanochemical
synthesis. [Reproduced with permission of the American Chemical
Society.]6

Research Achievements

Gp-A02 Advanced Analysis
Our group strives to understand unique ion transport/
storage phenomena at solid-state interfaces using
comprehensive analyses. We establish and improvevarious novel and advanced analytical techniques as well
as systematically apply them to typical model solid-stateinterfaces such as a well-defined film electrode on solid

electrolytes and glass-ceramics electrolytes suppliedby Gp-A01 and Gp-A04. Based on the results obtainedin collaboration with the theoretical calculations andsimulations conducted by Gp-A03, we establish scientificprinciples that enable the design of high-performancesolid-state interfaces.

Highlight 3

Tracer diffusion coefficients of Li ions in LixMn2O4 thin films observed byisotope exchange secondary ion mass spectrometry
N. Kuwata, G. Hasegawa, D. Maeda, N. Ishigaki, T. Miyazaki, J. Kawamura.
J. Phys. Chem. C. vol. 124, pp. 22981–22992 (2020)
Abstract
Tracer diffusion coefficients D* of lithium ions in LixMn2O4( 0.2 < x < 1 ) thin films were measured as a function of
the composition x using secondary ion mass spectrometry(SIMS). For this purpose, a new “step-isotope-exchange
method” was developed to observe the time dependence ofthe 6Li isotope concentration ratio in the LixMn2O4 film, whichcontacts a 6Li-enriched electrolyte to exchange Li+ ions. A
steep decrease in D* depending on the Li composition wasobserved for Li xMn2O4, with D* = 8 × 10−13 cm2 s−1 for x = 0.2
but decreases to 1.5× 10−17 cm2 s−1 for x = 1.0 (bulk diffusion~
coefficient, Db* ). Chemical diffusion coefficients D were alsoof thermodynamic factors. The thermodynamic factors
and interactions between Li+ ions strongly influenced themeasured in a range of 0.2 < x < 1.0 by an electrochemicalchemical diffusion coefficient. [Reproduced with permission

method and compared with the D* to evaluate the effectof the American Chemical Society.]

Highlight 4

Impact of oxygen defects on electrochemical processes and charge
compensation of Li-rich cathode material Li1.2Mn0.6Ni00.2O2-d
T. Nakamura, K. Ohta, Y. Kimura, K. Tsuruta, Y. Tamenori, R. Aso, H. Yoshida, K. Amezawa.
ACS Appl. Energy Mater. vol. 3, pp. 9703-9713 (2020)
Abstract
This work reports the impacts of oxygen vacancies
on the electrochemical properties of a Li-richcathode Li 1.2 Mn 0.6 Ni 0.2 O 2 - δ . In the initial charge, theoxygen-deficient Li 1.2 Mn 0.6 Ni 0.2 O 1.97 showed a larger
oxidation current due to oxygen release than theoxygen-stoichiometric Li 1.2 Mn 0.6 Ni 0.2 O 2 , suggestingthat a preliminary introduced oxygen vacancy
promoted further oxygen release during the initialcharge. Vigorous Mn redox was observed in theheavily oxygen-deficient Li 1.2 Mn 0.6 Ni 0.2 O 2 - δ phaseduring the charge/discharge. In contrast, Mn wasalmost inactive in the oxygen stoichiometric phase.
The modulation of oxygen defects can be an effective

strategy to control redox species in battery active
materials. [Reproduced with permission of theAmerican Chemical Society.]

Research Achievements

Gp-A03 Computational & Data Science
To construct a new theoretical framework for“Interface Ionics,” Gp-A03 introduces two strategies:
computational and data science approaches. For
this challenging target, deep collaborations with theother groups (A01, A02, & A04) are crucial. Recently,
we suggested insights into the ion transport in solid
elctrolytes and across electrolyte interfaces via DFT

calculations, together with the “Interface Ionics”
experimentalists. We also constructed the work flow
with machine learning techniques for efficient material
synthesis as well as an accurate force field set basedon the DFT calculations to investigate phenomena inlarger-scale disordered systems.

Highlight 5First-principles calculation study of Na+ superionic conduction mechanism
in W- and Mo-doped Na3SbS4 solid electrolytes
R. Jalem, A. Hayashi, Y. Tateyama, et al.
Chem. Mater. vol. 32, pp. 8373-8371 (2020) [A03-A04 joint paper]
Abstract
The guiding principle for the design of inorganic
compounds with a high ionic conductivity has been
extensively sought to realize next-generation allsolid-state batteries (ASSBs). Recently, a sulfide-type
Na+ ion conductor, cubic Na3SbS4 with W doping(Na2.88Sb 0.88W0.12S4), was reported. Its unprecedentedly
high ionic conductivity of 3.2 × 10–2 S cm–1 makes it achampion solid electrolyte for Na-ASSB (A. Hayashi
et al., Nat. Commun. 2019, 10, 5266). Herein density
functional theory molecular dynamics (DFT-MD)
calculations were performed for pristine, W-doped, andMo-doped Na3SbS4 to examine the ionic conduction
mechanism (Boltzmann factor vs. prefactor) andthe aliovalent cation dopant effects in Na3SbS4. Na
vacancies induced by cation doping play crucial roles
in superionic conductivity, while the diffusion process
is characterized by the concerted motion of Na+ ions.

A comparison between the two dopants, Mo6+ and
W6+, revealed that the conductivity enhancement canbe primarily explained by a decrease in the Na+ ion
activation energy, which is strongly correlated to theenlargement of the Na Wyckoff site cages due to thesmaller WS4/MoS4 tetrahedral volume relative to thehost SbS4 volume. In addition to explaining the superior
performance of W-doped Na3SbS4, this descriptor of
the pathway free volume suggests a general guiding
principle for superionic conduction that can be applied
to other cations. [Reproduced with permission of theAmerican Chemical Society.]

Highlight 6High-throughput production of force-fields or solid-state electrolyte materials
R. Kobayashi, M. Nakayama, et al.
APL Mater. vol. 8, pp. 081111-1–10 (2020).
[Selected as Featured Article & AIP Scilight]
Abstract
An automatic and high-throughput method to
produce interatomic force-fields for solid-stateelectrolyte materials is proposed. The proposed
method employs the cuckoo search algorithm with anautomatic update of the search space to optimize theparameters in empirical potentials and reproduce theradial and angular distribution functions and equilibrium
volume obtained from ab initio molecular dynamics
simulations. The force-fields for LiZr2(PO4)3 and LaF3
systems parameterized using the present method well
reproduce key physical properties required to study ion
conductivity of solid-state electrolyte materials. The

current approach, including the ab initio calculation tocreate reference data, takes only one or two days to
produce a force-field. This will greatly enhance the speedof exploration and screening of candidate materials.
[Reproduced with permission of the AIP Publishing.]

7

8

Research Achievements

Gp-A04 Design of Functional Interface
Gp-A04 designs innovative solid-state ionics
materials (SSIMs) through interface engineering. By
increasing the concentration of grain boundaries,
charge carriers are efficiently accumulated in SSIMs.
By further adjusting and optimizing the interfacial

structures,newfunctionalities
appear.
Suchfunctionalities are applied to new solid-state ionics
devices. Collaborative studies with members of Gp-A02
and Gp-A03 further accelerate the development of new
solid-state devices.

Highlight 7

Room-temperature manipulation ofmagnetization angle, achieved withan all-solid-state redox device
W. Namiki, T. Tsuchiya, M. Takayanagi, T. Higuchi, K. Terabe.
ACS Nano. vol. 14, pp. 16065–16072 (2020)
Abstract
An all-solid-state redox device, which was composedof a magnetite (Fe3O4) thin film and Li+ conducting
electrolyte thin film, was fabricated to manipulate
the magnetization angle at room temperature (RT).
Although this is a key technology for creating efficient
spintronics devices, it has yet to be achieved at RT
by other carrier doping methods. Variations in themagnetization angle and magnetic stability wereprecisely tracked via planar Hall measurements at RT.
The magnetization angle was reversibly manipulated at
10° by maintaining the magnetic stability. Meanwhile,

the manipulatable angle reached 56°, although themanipulation became irreversible when magnetic
stability was reduced. This large manipulation of themagnetic angle was achieved by tuning the 3d electron
number and modulation of the internal strain in Fe3O4
due to the insertion of high-density Li+ (approximately
1021 cm–3). This RT manipulation is applicable to highly
integrated spintronics devices due to its simple structure
and low electric power consumption. [Reproduced withpermission of the American Chemical Society.]

Highlight 8Integrating multiple materials science
projects in a single neural network
K. Hatakeyama-Sato and K. Oyaizu.
Comms. Mater. vol. 1, Article number: 49 (2020)
Abstract
In data-intensive science, machine learning plays acritical role in processing big data. However, the potentialof machine learning is limited in the field of materials
science due to difficulties treating complex real-worldinformation as a digital language. Here, we propose
using graph-shaped databases with a common format
to describe almost any materials science experimental
data digitally, including chemical structures, processes,
properties, and natural languages. The graphs can
express real-world data with little information loss.
Unlike traditional approaches, which require individualmodels to process each database and property, in
our approach, a single neural network treats versatilematerials science data collected from over ten
projects. Multitask learning of miscellaneous factors

increases the prediction accuracy of the parameterssynergistically by acquiring broad knowledge in thefield. The integration is beneficial for developing generalprediction models and for solving inverse problems
in materials science. [Reproduced with permission of
Springer Nature.]Activity Reports

Activity Reports
Conferences Partially Supported by the “Interface Ionics” ProjectSpecific session “18: Materials and ‘Interface Ionics’ for Solid-state Ionics
Devices” of the 33rd Fall Meeting of the Ceramic Society of Japan (Online)
Sep. 3-4, 2020

The first domestic research meeting centered on“Interface Ionics” was held as a special session during
the 33rd fall meeting of the Ceramic Society of Japan.
The session consisted of 24 lectures, including 1
keynote speech, 4 invited talks, 15 oral presentations,and 4 text presentations by researchers inside andoutside the project. Dr. Hideki Iba (Toyota Motor) gave
the keynote speech on current issues and future
prospects of all-solid-state batteries. Prof. Iriyama,

Prof. Akitoshi Hayashi, Osaka Prefecture Univ.

Prof. Amezawa, Prof. Nakayama, and Prof. Yabuuchi
gave invited talks about their research progress in the“Interface Ionics” project. The other researchpresentations focused on solid electrolytes with good
formability, high-capacity electrodes with an anionredox mechanism, synthesis of battery materials,
characterization of bulk and interface by structural
analyses, and first principles calculations. About 100
participants attended the online meeting.

Conferences Partially Supported by the “Interface Ionics” Project“All Solid-state Battery Special Session” in The 61st Battery Symposium inJapan (Online)
Nov. 18-20, 2020
Prof. Yasutoshi Iriyama, Nagoya Univ.
Lect. Munekazu Motoyama, Nagoya Univ.
Asst. Prof. Takayuki Yamamoto, Nagoya Univ.

The 61st Battery Symposium in Japan (Y. Iriyama,
Chair of Organizing Comittee) was held online. With
1742 participants, 299 video presentations werescreened in an on-demand style. Many researchers
from “Interface Ionics” participated and presented. On
the second day, the “All-solid-state battery special
session” was held. Recent progress of “Interface Ionics”
was reported in the special session, and the number ofvideo views was 795.

9

10Activity Reports

Symposiums and Seminars

The 2nd Public Symposium on “Interface Ionics” in Tokyo
International Forum (& Online)
Sep. 28, 2020

The 2nd Public Symposium on “Interface Ionics”
was held at the Tokyo International Forum on Sep.
28, 2020, and the symposium was streamed online.
For the more than 400 registered participants, this
symposium provided an opportunity for scientists,
engineers, and students to discuss diverse aspects ofinterfacial phenomena related to solid-state chemistry,science, and technology. This conference featured
three invited talks from academia and industrial
communities. Additionally, four representatives, one
from each group in “Interface Ionics,” presented recent
research progress in this project. These presentations
triggered exciting in-depth discussions throughout the
symposium.
Our first invited speaker was Prof. Akira Yoshino, who
was awarded the 2019 Nobel Prize in Chemistry. He
delivered an engaging talk related to the development
and history of commercial lithium-ion batteries andProf. Naoaki Yabuuchi, Yokohama National Univ.

their prospects in our daily life. Our second speaker,
Prof. Ryoji Kanno, is a pioneering researcher in lithiumion conducting solid-state electrolyte. He presented
the history of the research on solid-state electrolytewith an emphasis on sulfide-based materials and thematerials design methodology for a new generation ofsolid electrolytes. Finally, our third invited speaker, Dr.
Wataru Ogihara, a senior researcher from Nissan Motor
Corporation, shared the history and development ofelectric vehicles in Nissan and the future perspective ofelectrification of automobile applications.
This public conference was designed as an on-site/
online “hybrid” symposium. It successfully closed withenthusiastic discussions. Our next public symposium isscheduled for 2021. We anticipate sharing our advances
in “Interface Ionics” with all participants in the near
future.

Invited talks were delivered from three speakers at the Tokyo International Forum. From the left, Nobel Laureate Yoshino, Prof. Kanno, and Dr. Ogihara.

Members attending (on-site) the 2nd Public Symposium on “Interface Ionics.” In addition, over 300 members joined the online symposium.

Activity Reports

Symposiums and Seminars

The 2nd “Interface Ionics” Seminar (Online)
Sep. 30, 2020

Assoc. Prof. Takashi Nakamura, Tohoku Univ.

The 2nd “Interface Ionics” seminar was held online on
September 30, 2020. This seminar shared fundamental andstate-of-the-art knowledge on electrochemical phenomena
at solid electrolyte interafaces, discussed the latest
findings in interfacial ion/electron dynamics, and enhanced
collaborations in this research project. Highlights included
114 participants, 2 plenary lectures, 13 invited talks, and 7
short oral presentations from young researchers.
The plenary lecture by Prof. Tatsuya Kawada (Tohoku
University) provided an overview of interfacial phenomena
in high-temperature solid electrolyte devices such as solidoxide fuel cells. The second plenary lecture given by Prof.
Yasutoshi Iriyama (Nagoya University) discussed recent
studies on the interface of all-solid-state batteries. There wasa lively discussion on the differences and similarities between
high-temperature and room temperature solid electrolyte
systems. Afterwards, 13 professors gave invited talks about
their specialities. To promote collaborations in the research
program “Interface Ionics,” a wide variety of synthesis/
analysis/calculation techniques were introduced. From theoral presentations by students/post-docs, two outstanding
young researchers were awarded “Interface Ionics.” The 2nd“Interface Ionics” seminar provided a great opportunity toshare the latest research in the project and to enhance future
research cooperation. We are grateful to all of the speakers
and attendees.

“Interface Ionics” Award Winners
Satoshi Hiroi
Postdoctral researcher / JASRI (Ohara Gr.)I am honored to receive the “Interface Ionics” Award. Previous researchers in solidstate physics have applied X-ray total scattering measurements for structural analysis of
disordered materials. Recently, this technique has been recognized as a powerful tool forthe structural analysis of advanced materials due to its applicability to crystalline materials
and advances in the differential pair-distribution function (PDF) method. I plan to contributeto the progress of functional materials by expanding the capability of the structural
analyzing technique using total scattering measurements.

Koki Nakano
Doctoral student / Nagoya Inst. of Tech. (Nakayama Lab.)I am honored to receive the “Interface Ionics” award. First, I would like to express mysincerest gratitude to the professors who kindly teach me and group members who support
my research. Although the topic I discussed is evolving, I would like to reveal the mechanismof ionic transportation through solid electrolyte interfaces and contribute to the research
project “Interface Ionics.”

11

Newsletter vol.3
Publisher/Contact
Office for Scientific Research on Innovative Areas:
Science on Interfacial Ion Dynamics for Solid State Ionics Devices
TEL: +81-52-789-3576
E-mail: office@int-ionics.material.nagoya-u.ac.jp
https://interface-ionics.jp/en/index.html

Date of issue: March 2021