Mechanism studies on Li-ion conduction at the interface between inorganic/organic hybrid semi-solid electrolytes in Li-ion batteries for next generation electric vehicles
Toshiba has developed a new type of lithium-ion battery “SCiB™” using lithium titanate anode instead of conventional carbonaceous materials . Compared to other Lithium-ion batteries, the SCiB has remarkably improved safety features plus high-power, long-life and quick-charging, , and has been applied to idling stop systems (ISS), hybrid electric vehicles (HEV), electric vehicles (EV), and energy storage systems for power plant (ESS).
As such, requirements for next generation SCiB batteries have become diversified and not only focused on increased capacity, hence why our development has been covering a wide field in order to meet these individual requests: high-capacity technologies for EVs, high-power output and high-temperature durability technologies for PHEVs and HEVs, and low cost technologies for Pb-free ESS.
Toshiba has recently developed a hybrid electrolyte, with oxide based solid electrolyte particles coated with small amount of gel polymer electrolyte in order to reduce interfacial contact resistance between solids. A 12V class bipolar battery has been successfully constructed with the hybrid electrolyte, and can operate at freezing point or below . This new technology is important to overcome high internal resistance and/or low chemical stability of solid electrolytes which have been previously reported, and to realize high-power and high-energy-density batteries without any liquid electrolytes and sheet separators.
However, the lithium ion conduction mechanism of the hybrid electrolyte is still not fully understood. Not only self-diffusion but also dynamic phenomena in an electric field still needs to be clarified, and this cannot be investigated only with conventional ex-situ experiments. In a complex-modulus-spectroscopy study using an alternating electric field , we have identified differences between lithium-ion-conduction phenomena at the surface of hybrid electrolytes and those of conventional electrolytes. Further collaboration with specialists of complex-impedance-spectroscopy in a field of solid state Ionics is required in order to obtain a more thorough understanding of the conduction mechanism.
Description of Research
The aim of this study is to understand Li-ion behavior in the hybrid electrolyte by using not only analytical and/or experimental approach but also computational method. This study also aims at building a design guideline to develop a more powerful battery with the hybrid electrolyte through the conduction mechanism understanding. Toshiba has excellent facilities for materials synthesis, chemical analysis, cell preparation and electrochemical testing including electric furnaces (~1600 deg.C), milling machines (wet and dry), dry-rooms, glove-boxes, electrode coating machines, charge-discharge devices and analysis equipment such as complex impedance measuring device (Keysite E4990A), ICP, XRD, SEM, NMR, FT-IR etc..
The successful candidate (Fellow) will therefore be able to experience the entire process from material synthesis to battery testing at our laboratories during the research and gain a wide understanding. While we believe that experience is subservient to knowledge, the goal is to build a strong technology for the Toshiba business in the field of energy infrastructure and electric vehicles.
Required Knowledge and Skills
We are therefore searching for Fellowship candidates who specialize in solid state Ionics and electrochemical analysis. The candidates will be expected to build a design guideline to develop a more powerful battery with the hybrid electrolyte through the conduction mechanism understanding.
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