ORALS

Lithium ion batteries (LIBs) have been widely used as energy-storage systems for a variety of power devices. It is necessary to further develop LIBs toward high-functional devices, such as electric vehicles and mobile electronics. Nowadays, all-solid-state LIBs have been of much interest because of high energy densities and high safety. All solid-state LIBs gave a lot of advantages in terms of size, flexibility, cost, and performance. In the case of oxide-type all-solid-state LIBs, however, there are serious problems to be solved toward practical uses. For example, diffusion of lithium ions at their interfaces between different solid materials is still too poor to operate charge/discharge in batteries. Our group has studied high-quality crystals for applications as energy and environmental materials by using a flux method. The flux method is a nature-mimetic liquid-phase crystal growth technique. It is possible to construct a molten reaction field at any temperature with facile setup, and give a designed shape to crystals, including crystal faces, which has never been achieved using other methods like solid state reactions. Recently, we have proposed and applied the flux technique to battery materials to create “all-crystal (solid)-state LIBs”. We have expected that flux crystal growth gave (I) crystal-shape controls of active materials (and solid electrolytes), (II) construction of good interfaces in electrodes among cathodes, and (III) solid electrolytes and anodes. As a result, smooth ionic transportation through bulks and their interfaces would be realized in all-crystal (solid)-state LIBs. Our concept of using the flux crystal growth method would provide new aspects to make innovations in oxide-type all-solid-state LIBs as next-generation energy storage. The details of material and interfacial designs for next-generation batteries will be introduced in the SIPS2019. Acknowledgement: This research was partially supported by MEXT-Regional Innovation Ecosystems, JST-CREST (JPMJCR1322), JSPS Grant-in-Aid for Scientific Research (A) (25249089&17H01322) and JST-ALCA.

References:
(1) Hiromasa Shiiba, Nobuyuki Zettsu, Satoru Kida, Dae-wook Kim, Katsuya Teshima, Journal of Materials Chemistry A, 6 (2018) 22749-22757.
(2) Hiromasa Shiiba, Nobuyuki Zettsu, Miho Yamashita, Hitoshi Onodera, Randy Jalem, Masanobu Nakayama, Katsuya Teshima, The Journal of Physical Chemistry C, 122 (2018) 21755-21762.
(3) Dae-wook Kim, Shuhei Uchida, Hiromasa Shiiba, Nobuyuki Zettsu, Katsuya Teshima, Scientific Reports, 8 (2018) 11771_1-9.