Preparation and electrochemical characteristics of waste-tire char-based CFX for lithium-ion primary batteries

Ha Naeun,Jeong Seo Gyeong,Lim Chaehun,Ha Seongmin,Min Chung Gi,Choi Yusong,Lee Young-Seak 한국탄소학회 2023 Carbon Letters Vol.33 No.4

In this study, we investigate the opportunity of using waste tire char as a cathode material for lithium-ion primary batteries (LPBs). The char obtained by carbonizing waste tires was washed with acid and thermally fluorinated to produce CFX. The structural and chemical properties of the char and CFX were analyzed to evaluate the effect of thermal fluorination. The carbon structure of the char was increasingly converted to CFX structure as the fluorination temperature increased. In addition, the manufactured CFX-based LPBs were evaluated through electrochemical analysis. The discharge capacity of the CFX reached a maximum of 800 mAh/g, which is comparable to that of CFX-based LPBs manufactured from other carbon sources. On the basis of these results, the use of waste tire char-based CFX as a cathode material for LPBs is presented as a new opportunity in the field of waste tire recycling.

Correction: Preparation and electrochemical characteristics of waste‑tire char‑based CFX for lithium‑ion primary batteries

Naeun Ha,Seo Gyeong Jeong,Chaehun Lim,Seongmin Ha,Chung Gi Min,Yusong Choi,Young‑Seak Lee 한국탄소학회 2023 Carbon Letters Vol.33 No.6

통번역대학원생을 위한 한국어 번역 글쓰기 교과 과정 설계 연구

하나은 ( Ha Naeun ),윤창숙 ( Yoon Changsook ) 한국언어문화교육학회 2021 언어와 문화 Vol.17 No.1

This study proposes a Korean translation-writing course model for graduate students that emphasizes the importance of translators’creative writing skills. Such skills are vital in this era when human translators must compete against artificial intelligence (AI) machine translation software. Translation programs must provide courses that help students develop creative writing skills rather than only training them in direct translation; however, few graduate or undergraduate curriculums pay adequate attention to improving this aspect of students’writing skills. The 16-week course model proposed in this study focuses on incorporating creative writing skills not only into the initial translation process but also in editing and proof-reading; post-editing, which includes editing machine translation work; and trans-creation, which encompasses translating a source text into a target text by balancing translation and creative writing. Expanding translators’skills in this way will give them competitive advantages over machine translation software. (Busan University of Foreign Studies·Pusan National University)

탄소섬유강화플라스틱 유래 폐 탄소섬유로 제조된 불화탄소 기반 리튬일차전지의 전기화학적 특성

하나은 ( Naeun Ha ),임채훈 ( Chaehun Lim ),하성민 ( Seongmin Ha ),명성재 ( Seongjae Myeong ),이영석 ( Young-seak Lee ) 한국공업화학회 2023 공업화학 Vol.34 No.5

본 연구에서는 탄소섬유강화플라스틱(CFRP)을 열분해하여 얻은 폐 탄소섬유를 이용하여 기상 불소화를 통해 불화탄소를 제조하고 리튬일차전지의 환원극 소재로 재활용하고자 하였다. 먼저 열분해로 얻은 폐 탄소섬유의 물리화학적 특성을 파악하였으며, 이 폐 탄소섬유에 기상 불소화 효과를 평가하기 위하여 불화탄소의 구조적, 화학적 특성을 분석하였다. XRD 분석에 의해 폐 탄소섬유의 육각망탄소 적층구조(002피크)는 기상 불소화의 온도가 증가함에 따라 점차 불화탄소 구조(001피크)로 전환되었음을 확인하였다. 이 불화탄소를 이용하여 제조된 리튬일차전지의 방전용량은 최대 862 mAh/g이었다. 이는 다른 탄소 재료로 제조한 불화탄소 기반 리튬이온차전지의 방전용량과 비교하였을 때 우수한 성능을 보였다. 이러한 결과는 폐 CFRP 기반 폐탄소섬유를 이용한 불화탄소는 리튬일차전지의 환원극 소재로 활용할 수 있을 것으로 여겨진다. In this study, waste carbon fiber obtained by pyrolysis of carbon fiber reinforced plastic (CFRP) was used to produce carbon fluoride through vapor phase fluorination and recycled as a reducing electrode material for lithium primary batteries. First, the physicochemical properties of the waste carbon fiber obtained by pyrolysis were determined, and the structural and chemical properties of carbon fluoride were analyzed to evaluate the effect of vapor phase fluorination on the waste carbon fiber. XRD analysis confirmed that the hexagonal network carbon laminated structure (002 peak) of the waste carbon fiber was gradually converted into a carbon fluoride structure (CF_X, 001 peak) as the temperature of gas phase fluorination increased. The discharge capacity of the lithium primary battery produced using this carbon fluoride was up to 862 mAh/g. This was compared to the discharge capacity of carbon fluoride-based Li-ion batteries made of other carbon materials. These results suggest that carbon fluoride made from waste CFRP-based carbon fibers can be used as a reducing electrode material for Li-ion batteries.

Vitamin C down‐regulates VEGF production in B16F10 murine melanoma cells via the suppression of p42/44 MAPK activation

Kim, Ha Na,Kim, Hyemin,Kong, Joo Myung,Bae, Seyeon,Kim, Yong Sung,Lee, Naeun,Cho, Byung Joo,Lee, Seung Koo,Kim, Hang‐,Rae,Hwang, Young‐,il,Kang, Jae Seung,Lee, Wang Jae Wiley Subscription Services, Inc., A Wiley Company 2011 Journal of cellular biochemistry Vol.112 No.3

<P><B>Abstract</B></P><P>It is known that vitamin C induces apoptosis in several kinds of tumor cells, but its effect on the regulation of the angiogenic process of tumors is not completely studied. Vascular endothelial growth factor (VEGF) is the most well‐known angiogenic factor, and it has a potent function as a stimulator of endothelial survival, migration, as well as vascular permeability. Therefore, we have investigated whether vitamin C can regulate the angiogenic process through the modulation of VEGF production from B16F10 melanoma cells. VEGF mRNA expression and VEGF production at protein levels were suppressed by vitamin C. In addition, we found that vitamin C suppressed the expression of cyclooxygenase (COX)‐2 and that decreased VEGF production by vitamin C was also restored by the administration of prostaglandin E2 which is a product of COX‐2. These results suggest that vitamin C suppresses VEGF expression via the regulation of COX‐2 expression. Mitogen‐activated protein kinases are generally known as key mediators in the signaling pathway for VEGF production. In the presence of vitamin C, the activation of p42/44 MAPK was completely inhibited. Taken together, our data suggest that vitamin C can down‐regulate VEGF production via the modulation of COX‐2 expression and that p42/44 MAPK acts as an important signaling mediator in this process. J. Cell. Biochem. 112: 894–901, 2011. © 2010 Wiley‐Liss, Inc.</P>

Plasma treatment of CFX: the effect of surface chemical modification coupled with surface etching

Chaehun Lim,Seongmin Ha,Naeun Ha,Seo Gyeong Jeong,Young‑Seak Lee 한국탄소학회 2024 Carbon Letters Vol.34 No.2

불화탄소 전극의 열분해 연료유 기반 탄소 코팅이 리튬일차전지의 고율속 성능에 미치는 영향

이상엽 ( Sangyeop Lee ),하나은 ( Naeun Ha ),명성재 ( Seongjae Myeong ),임채훈 ( Chaehun Lim ),이세현 ( Sei-hyun Lee ),이영석 ( Young-seak Lee ) 한국공업화학회 2024 공업화학 Vol.35 No.4

불화탄소 기반 리튬일차전지(Li/CFX)의 활물질로 이용되는 불화탄소는 낮은 전도성에 기인한 열악한 율속 특성으로 방전 성능이 제한적이다. 따라서, 본 연구에서는 이를 극복하기 위하여 불화탄소에 열분해 연료유를 이용하여 탄소코팅을 진행하였고, 전기화학적 성능을 고찰하였다. 탄소 코팅에 의하여 불화탄소 표면에 무정형 탄소층이 형성되었으며, 열처리 온도에 따른 불화탄소의 표면 물리화학적 특성을 면밀히 고찰하였다. 상용 불화탄소를 450 ℃에서 열처리한 ARC@C450 샘플은 sp2 탄소 결합의 함량이 62%로 가장 크게 증가하였으며, 반이온성 C-F 결합이 가장 많이 형성되었다. 또한, ARC@C450 샘플을 환원극 활물질로 이용한 일차전지는 가장 높은 5 C 율속(392 mAh/g)에서 안정적인 방전 특성을 보였으며, Rct 값은 미처리 시료에 비하여 53% 감소하였다. 따라서, 본 연구에서는 불화탄소의 낮은 전도성을 극복하기 위한 방법으로 열분해 연료유 기반 탄소 코팅을 제안하며, 탄소 코팅된 불화탄소는 우수한 율속성능을 나타냄으로 고출력 일차전지로의 응용 가능성을 제시한다. The performance of carbon fluoride-based lithium primary batteries (Li/CFX) is limited due to poor rate capability resulting from the low conductivity of carbon fluoride, which is used as the active material. Therefore, in this study, we applied a carbon coating using pyrolysis fuel oil on carbon fluoride to overcome this limitation and considered its electrochemical performance. An amorphous carbon layer was formed on the surface of the carbon fluoride through carbon coating, and the surface physicochemical properties of the carbon fluoride were meticulously considered based on the heat treatment temperature. The advanced research chemical 1000 heat treated at 450 ℃ (ARC@C450) sample, which was commercial carbon fluoride heat-treated at 450 ℃, showed the largest increase in the concentration of sp2 carbon bonds (62%) and the highest formation of semi-ionic C-F bonds. Also, the primary battery using the ARC@C450 sample as a cathode active material exhibited stable discharge capability at the highest rate of 5 C (392 mAh/g), and the Rct value was reduced by 53% compared to the untreated sample. Therefore, we proposed pyrolysis fuel oil-based carbon coating as a method to overcome the low conductivity of carbon fluoride, and the carbon-coated carbon fluoride showed excellent rate performance, suggesting its potential application in high-power primary batteries.

인공지능을 이용한 뷰티 가상 테스터와 추천 시스템

오유진(Yujin Oh),김나은(Naeun Kim ),하란(Rhan Ha) 한국정보과학회 2021 한국정보과학회 학술발표논문집 Vol.2021 No.12

산소 플라즈마를 이용하여 율속 성능이 개선된 불화탄소 기반 리튬 일차전지의 제조 및 전기 화학적 특성

천서영 ( Seoyeong Cheon ),하나은 ( Naeun Ha ),임채훈 ( Chaehun Lim ),명성재 ( Seongjae Myeong ),이인우 ( In Woo Lee ),이영석 ( Young-seak Lee ) 한국공업화학회 2023 공업화학 Vol.34 No.5

일차전지 환원극의 활물질로 널리 사용되고 있는 불화탄소는 낮은 전기 전도도, 표면 에너지 및 전해질 투과도 등의 요인에 의하여 Li/CF_X 일차전지의 율속 성능 저하를 초래한다. 따라서 본 연구에서는 산소 플라즈마를 이용한 표면처리를 통하여 표면이 개질된 불화탄소를 리튬 일차전지의 환원극으로 사용하여 전지 성능을 향상시키고자 하였다. XPS 및 XRD 분석을 통해 산소 플라즈마 처리에 의해 변화된 불화탄소의 표면 화학적 특성 및 결정 구조 변화를 분석하였으며, 이에 따른 리튬 일차전지의 전기 화학적 특성에 대한 변화를 분석하고 고찰하였다. 그 결과, 탄소 대 불소비율(F/C) 비율이 가장 낮은 산소 플라즈마 처리 조건(7.5 min)에서 반이온성 C-F 결합이 가장 많이 형성되었다. 또한, 이 조건에서 제조된 불화탄소를 환원극의 활물질로 사용한 일차전지는 가장 높은 3 C의 율속 특성을 보였으며, 고율 속에서도 비교적 높은 용량(550 mAh/g)을 유지하였다. 본 연구를 통하여, 산소 플라즈마 처리를 통해 불화탄소의 불소 함량 및 탄소-불소 간의 결합 유형을 조정하여 고율속 성능을 가진 리튬 일차전지를 제조할 수 있었다. The high-rate performance is limited by several factors, such as polarization generation, low electrical conductivity, low surface energy, and low electrolyte permeability of CF_X, which is widely used as a cathode active material in the lithium primary battery. Therefore, in this study, we aimed to improve the battery performance by using carbon fluoride modified by surface treatment using oxygen plasma as a cathode for lithium primary batteries. Through XPS and XRD analysis, changes in the surface chemical characteristics and crystal structure of CF_X modified by oxygen plasma treatment were analyzed, and accordingly, the electrochemical characteristics of lithium-ion primary batteries were analyzed and discussed. As a result, the highest number of semi-ionic C-F bonds were formed under the oxygen plasma treatment condition (7.5 minutes) with the lowest fluorine to carbon (F/C) ratio. In addition, the primary cell prepared under this condition using carbon fluoride as the active material of the cathode showed the highest 3 F/C(3 C rate-performance) rate-performance and maintained a relatively high capacity (550 mAh/g) even at high rates. In this study, it was possible to produce lithium primary batteries with high-rate performance by adjusting the fluorine contents of carbon fluoride and the type of carbon-fluorine bonding through oxygen plasma treatment.

High efficiency and flux separation of water‑in‑oil emulsions of superhydrophobic microporous carbon aerogels

Seongjae Myeong,Chaehun Lim,Seongmin Ha,Chung Gi Min,Naeun Ha,Young‑Seak Lee 한국탄소학회 2024 Carbon Letters Vol.34 No.4