Young Geun Yoo

Interfacial Adsorption and Redox Coupling of Li4Ti5O12 with Nanographene for High-Rate Lithium Storage

Despite the many efforts to solve the problem associated with lithium storage at high rates, it is rarely achieved up until now. The design with experimental proof is reported here for the high rate of lithium storage via a core-shell structure composite comprised of a Li4Ti5O12 (LTO) core and a nanographene (NG) shell. The LTO-NG core-shell was synthesized via a first-principles understanding of the adsorption properties between LTO and NG. Interfacial reactions are considered between the two materials by a redox coupling effect. The large interfacial area between the LTO core and the NG shell resulted in a high electron-conducting path. It allowed rapid kinetics to be achieved for lithium storage and also resulted in a stable contact between LTO and NG, affording cyclic performance stability.

Insights into the Li Diffusion Dynamics and Nanostructuring of H2Ti12O25 To Enhance Its Li Storage Performance

Dodecatitanate H2Ti12O25 crystal has a condensed layered structure and exhibits noteworthy Li storage performance that makes it an anode material with great potential for use in Li-ion batteries. However, an unknown Li diffusion mechanism and a sluggish level of Li dynamics through elongated diffusion paths inside this crystal has impeded any forward development in resolving its limited rate capability and cyclic stability. In this study, we investigated the Li diffusion dynamics inside the H2Ti12O25 crystal that play an essential role in Li storage performance. A study of density functional theory combined with experimental evaluation confirmed a strong dependence of Li storage performance on its diffusion. In addition, a nanostructured H2Ti12O25 containing a bundle of nanorods is developed via the introduction of a kinetic gap during the structural transformation, which conferred a significantly shortened diffusion time/length for Li in H2Ti12O25. The nanostructured H2Ti12O25 has high specific capacity (∼230 mAh g(-1)) and exhibits enhanced cyclic stability and rate capability compared with conventional bulky H2Ti12O25. The H2Ti12O25 proposed in this study has high potential for use as an anode material with excellent safety and stability.

Energy storage systems based on endoskeleton structuring

As electronic devices have continued to advance, consistent with Moores law, it is clear that the development of technology can create new types of products and jobs and even industrial sectors. While human integrated devices, storage of fluctuating energy sources and electric transports are required in the near future, one field of electronics has not fully developed, – i.e., energy storage devices. In order to overcome this impediment, we developed a new approach of energy systems that is inspired by the difference in evolutionary genealogy between animals, i.e., insects (exoskeleton) versus vertebrates (endoskeleton). The new energy storage technology proposed here includes an endoskeleton architecture similar to vertebrates, which (1) provides flexibility for future mobile/human integrated electrics, (2) ensures the scalability of devices for the storage of fluctuating energy sources and (3) solves safety issues associated with energy storage devices in electric vehicles.