• Bulletin of the Korean Chemical Society
• /
• 제35권5호
• /
• pp.1305-1311
• /
• 2014

The nickel oxide, the most widely used cathode material for the molten carbonate fuel cell (MCFC), has several disadvantages including NiO dissolution, poor mechanical strength, and corrosion phenomena during MCFC operation. The surface modification of NiO with lanthanum maintains the advantages, such as performance and stability, and suppresses the disadvantages of NiO cathode because the modification results in the formation of $LaNiO_3$ phase which has high conductivity, stability, and catalytic activity. As a result, La-modified NiO cathode shows low NiO dissolution, high degree of lithiation, and mechanical strength, and high cell performance and catalytic activity in comparison with the pristine NiO. These enhanced physico-chemical and electrochemical properties and the durability in marine environment allow MCFC to marine application as a auxiliary propulsion system.

• 산업기술연구
• /
• 제43권1호
• /
• pp.43-48
• /
• 2023

Spinel LiNi_0.5Mn_1.5O₄ (LNMO) has been considered as one of most promising cathode material, because of its low-cost and competitive energy density. However, 4.7V vs. Li/Li⁺ of high operating potential facilitates electrolyte degradation on cathode-electrolyte interface during charge-discharge process. In particular, commercial polyvinylidene fluoride (PVDF) is not sutaible for LNMO cathode binder because its weak van der waals force induces thick and non-uniform coverage on the cathode surface. In this review, we study high performance binders for LNMO cathode, which forms uniform coating layer to prevent direct contact between electrolyte and LNMO particle as well as modifying high quality cathode electrolyte interphase, improved cell performace.

• 전기화학회지
• /
• 제13권3호
• /
• pp.203-210
• /
• 2010

용융탄산염 연료전지(MCFC)의 양극으로 사용되는 NiO는 $650^{\circ}C$의 용융탄산염과 산소 분위기 조건에서 안정하고 높은 전기 전도도를 가지는 장점이 있다. 그러나, 장시간 운전 시 양극에서 전해질로의 Ni dissolution은 전지 내부의 단락을 초래하여 전지의 수명을 단축시킨다. 본 연구에서는 대체 전극물질로서 코발트와 나이오븀을 코팅시킨 NiO 전극을 제조하였으며, 이렇게 제조된 전극은 기존 NiO전극과 비교하여 낮은 Ni dissolution과 안정되고 우수한 전기화학 성능을 보임을 확인하였다.

• 한국세라믹학회지
• /
• 제55권4호
• /
• pp.358-363
• /
• 2018

To improve the polarization property of cathodes, which is the main factor limiting the performance of protonic ceramic fuel cells (PCFCs), $K_2NiF_4-type$ $Pr_2NiO_{4+{\delta}}$, which is expected to exhibit a triple conducting property (proton, oxygen ion, and hole conductions) was applied to PCFCs and its properties were investigated. Low-temperature microwave heat-treatment was used to achieve both sufficient interface adhesion between the electrolyte and the cathode layers and suppression of the secondary phase formation due to migration of elements such as barium and cerium. Through this fabrication method, a high performance of $0.82W{\cdot}cm^{-2}$ and low ohmic resistance of $0.06{\Omega}{\cdot}cm^2$ were obtained in an $Ni-BaCe_{0.55}Zr_{0.3}Y_{0.15}O_{3-{\delta}}$ | $BaCe_{0.55}Zr_{0.3}Y_{0.15}O_{3-{\delta}}$ | $Pr_2NiO_{4+{\delta}}$ single cell at $650^{\circ}C$. This result verifies that the $K_2NiF_{4+{\delta}}-type$ cathode shows good chemical compatibility which, in turn, will make it a potent candidate as a PCFC cathode.

• 전기화학회지
• /
• 제22권4호
• /
• pp.172-176
• /
• 2019

The first commercialized cathode material, $LiCoO_2$, suffers from disadvantages such as high cost and toxicity and also possesses safety problems. The nickel-rich $LiNi_{0.9}Mn_{0.1}O_2$ cathode material, used as an alternative to $LiCoO_2$, has highly reversible capacity and high energy density. So, the nickel-rich $LiNi_{0.9}Mn_{0.1}O_2$ cathode material is widely used as an alternative to $LiCoO_2$ due to its highly reversible capacity and high energy density. However, $LiNi_{0.9}Mn_{0.1}O_2$ has several disadvantages as well, such as poor cycle performance and poor thermal instability. To address these problems, we synthesized a new material, $LiNi_{0.5}Mn_{0.5}O_2$, as a shell on the surface of a core to suppress the surface degradation. The new material showed high structural and thermal stabilities and could also maintain a high capacity. The capacity retention of the core-shell cathode (87.7%) was better than that of the core cathode (76.9%) after 50 cycles. Analysis using differential scanning calorimetry revealed that the heat generation in the core-shell cathode ($65.9Jg^{-1}$) was lower than that in the core cathode ($559.7Jg^{-1}$).

• 한국신재생에너지학회:학술대회논문집
• /
• 한국신재생에너지학회 2007년도 춘계학술대회
• /
• pp.133-136
• /
• 2007

Perovskite-structured samarium strontium cobaltite (SSC), which is mixed ionic electronic conductor (MIEC), is considered as a promising cathode material for intermediate temperature-operating solid oxide fuel cell (SOFC) due to its high electrocatalytic property. Cathode material containing cobalt (Co) is unstable at high temperature and has a relatively high thermal expansion property. In this paper, Sm-Sr-(Co,Fe,Ni)-O system with perovskite and spinel structures was investigated in terms of electrochemical property and thermal expansion property, respectively. Area specific resistance (ASR) was measured by ac impedance spectroscopy to investigate the electrochemical property of cathode, and thermal expansion coefficient (TEC) was measured by using dilatometer. Micro structure of cathode was observed by scanning electron microscopy. Perovskite-structured $Sm_{0.5}Sr_{0.5}CoO_{3-\delta}$ showed the ASR of $0.87{\Omega}/cm^{2}$, and $Sm_{0.5}Sr_{0.5}NiO_{3-\delta}$, which actually has a spinel structure, showed the lowest TEC value of $13.3{\times}10^{-6}/K$.

• 한국전기전자재료학회논문지
• /
• 제37권2호
• /
• pp.215-222
• /
• 2024

Ni-rich cathode materials have been developed as the most promising candidates for next-generation cathode materials for lithium-ion batteries because of their high capacity and energy density. In particular, the electrochemical performance of lithium-ion batteries could be enhanced by increasing the contents of nickel ion. However, there are still limitations, such as low structural stability, cation mixing, low capacity retention and poor rate capability. Herein, we have successfully developed the nanorod-type Ni-rich cathode materials by using co-precipitation method. Particularly, the nanorod-type primary particles of LiNi_0.7Co_0.15Mn_0.15O₂ could facilitate the electron transfer because of their longitudinal morphology. Moreover, there were holes at the center of secondary particles, resulting in high permeability of the electrolyte. Lithium-ion batteries using the prepared nanorod-type LiNi_0.7Co_0.15Mn_0.15O₂ achieved highly improved electrochemical performance with a superior rate capability during battery cycling.

• 한국재료학회지
• /
• 제18권7호
• /
• pp.384-388
• /
• 2008

Hydrogen production via high high-temperature steam electrolysis consumes less electrical energy than compared to conventional low low-temperature water electrolysis, mainly due to the improved thermodynamics and kinetics at elevated temperaturetemperatures. The elementalElemental powders of Cu, Ni, and YSZ are were used to synthesize high high-temperature electrolysis cathodecathodes, of Ni/YSZ and Cu/YSZ composites, by mechanical alloying. The metallic particles of the composites were uniformly covered with finer YSZ particles. Sub-micron sized pores are were homogeneously dispersed in the Ni/YSZ and Cu/YSZ composites. In this study, The cathode materials were synthesized and their Characterizations properties were evaluated in this study: It was found that the better electric conductivity of the Cu/YSZ composite was measured improved compared tothan that of the Ni/YSZ composite. Slight A slight increase in the resistance can be produced for in a Cu/YSZ cathode by oxidation, but it this is compensated offset for by a favorable thermal expansion coefficient. Therefore, Cu/YSZ cermet can be adequately used as a suitable cathode material of in high high-temperature electrolysis.

• Journal of Electrochemical Science and Technology
• /
• 제14권3호
• /
• pp.272-282
• /
• 2023

Ni-rich layered oxides cathode has recently gained attention as an advanced cathode material due to their applicable energy density. However, as the Ni component in the layered site is increased, the high reactivity of Ni⁴⁺ results in parasitic reaction associated with decomposing electrolyte, which leads to a rapid decreasing the lifespan of the cell. The electrolyte additive triallyl borate (TAB) improves interfacial stability, leading to a stable cathode-electrolyte interphase (CEI) layer on the LNCM83 cathode. A multi-functionalized TAB additive can produce a uniformly distributed CEI layer via electrochemical oxidation, which implies an increase in long-term cycling performance. After 100 cycles at elevated temperature, the cell tested by 0.75 TAB retained 88.3% of its retention ratio, whereas the cell performed by TAB-free electrolyte retained 64.1% of its retention. Once the TAB additive formed CEI layers on the LNCM83 cathode, it inhibited the decomposition of carbonate-based solvents species in addition to the dissolution of transition metal components from the cathode. The addition of TAB to LNCM83 cathode material is believed to be a promising way to increase the electrochemical performance.

• 한국재료학회지
• /
• 제30권11호
• /
• pp.636-640
• /
• 2020

Due to the serious air pollution problem, interest in eco-friendly vehicles is increasing. Solving the problem of pollution will necessitate the securing of high energy storage technology for batteries, the driving force of eco-friendly vehicles. The reason for the continuing interest in the transition metal oxide LiMO₂ as a cathode material with a layered structure is that lithium ions reveal high mobility in two-dimensional space. Therefore, it is important to investigate the effective intercalation and deintercalation pathways of Li⁺, which affect battery capacity, to understand the internal structure of the cathode particle and its effect on the electrochemical performance. In this study, for the cathode material, high nickel Ni_0.8Co_0.1Mn_0.1(OH)₂ precursor is synthesized by controlling the ammonia concentration. Thereafter, the shape of the primary particles of the precursor is investigated through SEM analysis; X-ray diffraction analysis is also performed. The electrochemical properties of LiNi_0.8Co_0.1Mn_0.1O₂ are evaluated after heat treatment.