Dong Hyun Kim

Mr. Dong Hyun Kim

orcid

Research Focus & Metrics

Academic Career Length

3Years (2024-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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29 July 2024 in Molecules
Verified
Journal Article
Open access
PDF file
JYJinUk Yoo
JinUk Yoo
DKDong Hyun Kim
Dong Hyun Kim
TCTae Min Choi
Tae Min Choi
EJEun Su Jung
Eun Su Jung
HLHwa Rim Lee
Hwa Rim Lee
SPSung Gyu Pyo
Sung Gyu Pyo
With the gradual miniaturization of electronic devices and the increasing interest in wearable devices, flexible microelectronics is being actively studied. Owing to the limitations of existing battery systems corresponding to miniaturization, there is a need for flexible alternative power sources. Accordingly, energy harvesting from surrounding environmental systems using fluorinated polymers with piezoelectric properties has received significant attention. Among them, polyvinylidene fluoride (PVDF) and PVDF co-polymers have been researched as representative organo-piezoelectric materials because of their excellent piezoelectric properties, mechanical flexibility, thermal stability, and light weight. Electrospinning is an effective method for fabricating nanofibrous meshes with superior surface-to-volume ratios from polymer solutions. During electrospinning, the polymer solution is subjected to mechanical stretching and in situ poling, corresponding to an external strong electric field. Consequently, the fraction of the piezoelectric β-phase in PVDF can be improved by the electrospinning process, and enhanced harvesting output can be realized. An overview of electrospun piezoelectric fibrous meshes composed of PVDF or PVDF co-polymers to be utilized is presented, and the recent progress in enhancement methods for harvesting output, such as fiber alignment, doping with various nanofillers, and coaxial fibers, is discussed. Additionally, other applications of these meshes as sensors are reviewed.

3 November 2024 in Applied Spectroscopy Reviews
Verified
Journal Article
Closed access
EJEun Su Jung
Eun Su Jung
JCJin Hyun Choe
Jin Hyun Choe
JYJinUk Yoo
JinUk Yoo
TCTae Min Choi
Tae Min Choi
HLHwa Rim Lee
Hwa Rim Lee
SPSung Gyu Pyo
Sung Gyu Pyo

1 January 2024 in International Journal of Energy Research
Verified
Journal Article
Open access
JYJinUk Yoo
JinUk Yoo
DKDong Hyun Kim
Dong Hyun Kim
SPSung Gyu Pyo
Sung Gyu Pyo
Electrospinning enables the rapid and facile production of nanofibers with desired structures and morphologies at room temperature and ambient pressure. These nanofibers are suitable cathode, anode, and separator materials for Li‐ion batteries (LIBs) because of their one‐dimensional(1‐D) structures and mechanical strength as well as their ability to enable rapid Li‐ion transport through short diffusion pathways. The use of electrospun nanofibers in LIBs can lead to better battery rechargeability, lifespan, and performance than those of existing LIBs. In this review article, we first discuss the problems associated with the cathode, anode, and separator materials currently used in LIBs. Next, we describe the improvements achieved by incorporating electrospun nanofibers as cathode, anode, and separator materials in LIBs. We believe that electrospun nanofibers can promote the advancement of LIB technology to realize very‐high‐energy‐density energy storage systems.

21 September 2024 in Micromachines
Verified
Journal Article
Open access
PDF file
JYJinUk Yoo
JinUk Yoo
DKDong Hyun Kim
Dong Hyun Kim
EJEun Su Jung
Eun Su Jung
TCTae Min Choi
Tae Min Choi
HLHwa Rim Lee
Hwa Rim Lee
SPSung Gyu Pyo
Sung Gyu Pyo
Nanogenerators have garnered significant interest as environmentally friendly and potential energy-harvesting systems. Nanogenerators can be broadly classified into piezo-, tribo-, and hybrid nanogenerators. The hybrid nanogenerator used in this experiment is a nanogenerator that uses both piezo and tribo effects. These hybrid nanogenerators have the potential to be used in wearable electronics, health monitoring, IoT devices, and more. In addition, the versatility of the material application in electrospinning makes it an ideal complement to hybrid nanogenerators. However, despite their potential, several experimental variables, biocompatibility, and harvesting efficiency require improvement in the research field. In particular, maximizing the output voltage of the fibers is a significant challenge. Based on this premise, this study aims to characterize hybrid nanogenerators (HNGs) with varied structures and material combinations, with a focus on identifying HNGs that exhibit superior piezoelectric- and triboelectric-induced voltage. In this study, several HNGs based on coaxial structures were fabricated via electrospinning. PVDF-HFP and PAN, known for their remarkable electrospinning properties, were used as the primary materials. Six combinations of these two materials were fabricated and categorized into homo and hetero groups based on their composition. The output voltage of the hetero group surpassed that of the homo group, primarily because of the triboelectric-induced voltage. Specifically, the overall output voltage of the hetero group was higher. In addition, the combination group with the most favorable voltage characteristics combined PVDF-HFP@PAN(BTO) and PAN hollow, boasting an output voltage of approximately 3.5 V.