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Kim, Jongjung

Publications and source records attributed to Kim, Jongjung.

Modification of lithium electrodeposition behavior by variation of electrode distance

Developing a better understanding and control over the lithium electrodeposition behavior will assist with the commercial application of lithium metal anodes for rechargeable batteries. Despite intensive research over the past decade, our understanding of the deposition of lithium is limited. Here a new observation on the effect of distance between the working electrode and the counter electrode for electrochemical lithium deposition behavior is reported. From this fundamental investigation of distance, the high lithium ion concentration regions formed by release of lithium ions from the counter electrode modify the lithium deposition behavior on the working electrode, resulting in the generation of non-uniform lithium dendrites with a thick diversely composed surface film. Alternatively, increasing the distance between the electrodes results in the deposition of a spherical lithium morphology with a thin LiF rich surface film. Here, this fundamental study provides a deeper understanding of correlation between lithium deposition behavior and electrode separation and provides insight to inhibit lithium dendrite formation.

25 ENERGY STORAGE↗

Casein from Bovine Milk as a Binder for Silicon Based Electrodes

Silicon is a promising anode material for lithium ion batteries due to the high theoretical capacity (∼3600mAh/g). However, silicon-based electrodes face rapid degradation due to the extensive volume variation (∼300%) during the lithiation/delithiation process. Binders used in the electrode fabrication play a crucial role for silicon electrodes since it can reduce the mechanical fracture during the cycling process. Recent investigations suggest that in addition to the importance of the mechanical properties of the binder, the chemical reactions between the binder and the surface of the silicon particles also contribute to stabilization. Further investigations suggest that functionalized small molecules can also modify the surface of silicon particles and stabilize cycling. An inexpensive, environmentally friendly alternative has been investigated as a binder for silicon electrodes. Casein is a milk protein found in bovine milk rich in amine groups and carboxylic acid groups which can form bonds with the silanol groups in silicon. A comparative study conducted between PVDF and Casein as binders have shown that when casein was used as binder, it shows better performance compared to PVDF. Surface morphology and solid electrolyte interphase (SEI) was analyzed using electron microscopy techniques and spectroscopic methods and the results will be discussed.

36 MATERIALS SCIENCE↗