Session 1: Next-Generation Cell Materials
This session discussed light and specialty-EV market development and advances in the technology and market of Lithium-Ion batteries that increasingly power these vehicles.
Session Chairman:
Yoshio Ukyo, Professor, Office of Society-Academia Collaboration for Innovation (SACI), Center for Advanced Science and Innovation, Kyoto University
Dr. Yoshio Ukyo got PhD in Metallurgy in 1981 and joined Toyota Central Research and Development Laboratories Incorporation (TCRDL). His research area in TCRDL includes synthesis and analysis of inorganic
materials for automotive catalyst and energy storage. He spent about 15 years for the development of lithium ion battery for hybrid vehicle. He has been Senior Fellow of TCRDL and now research adviser
of TCRDL. He joined to Kyoto University from this April and a member of national project on battery called RISING (Research and Development Initiative for Scientific Innovation of New Generation
Batteries).
Session Chairman:
Martin Winter, Chair, Applied Material Science for Energy Conversion and Storage, MEET Battery Research Center, Institute of Physical Chemistry,
University of Muenster
Prof. Martin Winter's main research interests are in applied electrochemistry, materials electrochemistry and inorganic chemistry and technology. He is the past president of the International Battery
Materials Association (IBA), Past Chair of the Division of Electrochemical Energy Storage and Conversion of International Society of Electrochemistry (ISE), and Technical Editor of the Journal
of The Electrochemical Society (ECS). Currently, he is the spokesperson of the LIB2015 Innovation Alliance of the BMBF (Germany Ministry of Education and Research) and a member of the German National
Platform E-Mobility (NPE).
SESSION AGENDA
Next Generation Li-Ion Cell Materials
Yoshio Ukyo, Professor, Office of Society-Academia Collaboration for Innovation (SACI), Center for Advanced Science and Innovation, Kyoto University
Advanced Materials Development for Li-Ion Batteries
Kisuk Kang, Professor, Department of Materials Science and Engineering, College of Engineering, Seoul National University
High-performance and cost-effective rechargeable batteries are key to the success of electric vehicles and large-scale energy storage systems. Extensive research has focused on the development
of new high-energy electrodes that can store more lithium. However, the current status of lithium batteries based on redox reactions of heavy transition metals still remains far below the
demands required for the proposed applications. In this presentation, we introduce two novel approaches toward transition metal-free cathode materials.
In the first part, it is demonstrated by using tunable functional groups on graphene nano-platelets as redox centers. The electrode can deliver high capacity of 250 mAh g−1,
power of 20 kW kg−1 in an acceptable cathode voltage range, and provide excellent cyclability up to thousands of repeated charge/discharge cycles. The simple, mass-scalable
synthetic route for the functionalized graphene nano-platelets is also proposed.
In the second part, we utilize a redox center from biological system. Energy transduction and storage in biological systems involve multiply coupled, stepwise reduction/oxidation of energy-carrying
molecules such as adenosine triphosphate (ATP), nicotinamide, and flavin cofactors. Here, we demonstrate a biomimetic approach to design high-performance energy devices based on the analogy
between energy-storage phenomena of mitochondria and lithium rechargeable batteries. It is found that flavins such as vitamin B2 and lumiflavine are capable of reversibly storing lithium
by using redox-active nitrogen atoms in the diazabutadiene motif during battery operation. The energy density of the flavin cathode (i.e. 510 Wh kg−1 for lumiflavine)
can compete with those of the commercial inorganic electrode materials such as LiFePO4.
Materials and Application Challenges of Layered Li-Excess Mn-Ni Oxide Cathode
Nick Wu, Distinguished Professor, Department of Chemical Engineering, National Taiwan University
The class of layered Li-rich Mn-transition metal oxides with a general formula of Li1+x(Mn,M)1-xO2 has lately drawn attention due to their high capacities greater
than 200 mAh/g. In these materials, the excess Li ion gives rise to the presence of inter-grown Li2MnO3 within Li(Mn,M)O2 matrix to form a layered “composite”
structure. Li2MnO3 is transformed to electrochemically active MnO2 by removal of Li+ upon charging above 4.5 V (versus Li/Li+) and stabilizes
the layered structure under deep lithiation/de-lithiation cycles. This presentation discuss on the synthesis and application issues of Li1+x(Mn0.6Ni0.4)1-xO2.
- Synthesis and fundamental properties:
- continuously stirred reactor process for making spherical powder
- synthesis-structure-performance relationships
- inhibition of potential fading
- oxide/graphite full cell charateristics
- Electronic conductivity issue:
- surface conductive coating.
- conductive-coated Al current collector
- Characterization of Si/oxide full-cell
- Li-ion compensation
- Voltage-capacity relation
Element Selective Evaluation of Cation Mixing by Anomalous Scattering X-ray Diffraction
Kenji Sato, Assistant Chief Engineer, Technology Development Division,
Honda R&D
Specific Bragg reflection intensities of Li-rich layered oxide were monitored on scanning the X-ray energy around the K-edge of Ni, Co and Mn. The experiments were conducted at BL28XU of SPring8.
Site exchange of Li and transition metal cations can be detected by intensity change of anomalous scattering. We can identify the transition metal element engaged in cation mixing by knowing
at which absorption edge of elements the intensity change occurred. This new method can be a powerful tool to study degradation mechanism of battery active materials.
Interface between Lithium and Solid Electrolytes
Osamu Yamamoto, Professor Emeritus, Mie University
Lithium metal is the best anode candidate for high energy density batteries, because it has very high theoretical specific capacity of 3861 mAh g-1. However, the formation of lithium
dendrite during lithium deposition limits the use of lithium metal as the anode in lithium batteries with liquid electrolyte. Much effort has recently been focused on lithium metal electrode
with solid electrolytes. This presentation will discuss the key issues facing a lithium dendrite formation between lithium metal and solid electrolyte.. These issues include:
- Stability of the interface between lithium metal and solid polymer electrolytes
- Lithium dendrite formation on the interface of lithium metal and polymer electrolytes
- Stability of the interface between lithium meal and garnet-type solid lithium ion conductor of Li7La3Zr2O12
- Lithium dendrite formation on the interface of lithium metal and Li7La3Zr2O12
