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플루오린 함량 제어를 통한 LiVPO₄O_1-xF_x 합성 및 리튬 이차전지 양극소재 전기화학 특성 분석 (Synthesis and Investigation of LiVPO₄O_1-xF_xvia Control of the Fluorine Content for Cathode of Lithium-ion Batteries)

김민경;이동휘;여찬규;최수연;최치원;윤현민
- 한국분말재료학회지
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- 제30권6호
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- pp.516-520
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- 2023
Highly safe lithium-ion batteries (LIBs) are required for large-scale applications such as electrical vehicles and energy storage systems. A highly stable cathode is essential for the development of safe LIBs. LiFePO₄ is one of the most stable cathodes because of its stable structure and strong bonding between P and O. However, it has a lower energy density than lithium transition metal oxides. To investigate the high energy density of phosphate materials, vanadium phosphates were investigated. Vanadium enables multiple redox reactions as well as high redox potentials. LiVPO₄O has two redox reactions (V⁵⁺/V⁴⁺/V³⁺) but low electrochemical activity. In this study, LiVPO₄O is doped with fluorine to improve its electrochemical activity and increase its operational redox potential. With increasing fluorine content in LiVPO₄O_1-xF_x, the local vanadium structure changed as the vanadium oxidation state changed. In addition, the operating potential increased with increasing fluorine content. Thus, it was confirmed that fluorine doping leads to a strong inductive effect and high operating voltage, which helps improve the energy density of the cathode materials.
https://doi.org/10.4150/KPMI.2023.30.6.516 인용 PDF

에어로졸 증착한 세라믹/금속 복합막의 금속 함량에 따른 습도 감지 특성 연구 (Study of Humidity Sensing Properties Related to Metal Content of Aerosol Deposited Ceramic/Metal Composite Films)

김익수;구상모;박철환;신원호;이동원;오종민
- 한국전기전자재료학회논문지
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- 제34권5호
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- pp.314-320
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- 2021
Controlling ambient humid condition through high performance humidity sensors has become important for various fields, including industrial process, food storage, and the preservation of historic remains. Although aerosol deposited humidity sensors using ceramic BaTiO₃ (BT) material have been widely studied because of their longtime stability, there remain critical disadvantages, such as low sensitivity, low linearity, and slow response/recovery time in case of the sensors fabricated at room temperature. To achieve superior humidity sensing properties even at room temperature condition, BT-Cu composite films utilizing aerosol deposition (AD) process have been proposed based on the percolation theory. The BT-Cu composite films showed gradually improved sensing properties until the Cu concentration reached 15 wt% in the composite film. However, the excessive Cu (above 30 wt%) containing BT-Cu composite films showed a rapid decrease of the sensing properties. The results of observed surface morphology of the AD fabricated composite films, to figure out the metal filler effect, showed correlation between surface topography as well as size and the amount of open pores according to the metal filler content. Overall, it is very important not only dielectric constant of the humidity sensing films but also microstructures, because they affect either the variation range of capacitance by ambient humidity or adsorption/desorption of ambient humidity onto/from the humidity sensing films.
https://doi.org/10.4313/JKEM.2021.34.5.314 인용 PDF KSCI