ACS Applied Energy Materials
·
2023
·
IF 6.4
Bin Hu,Jiaqi Peng,Dongming Liu,Mingli Wu,Yuanyuan Wei,Bin Huang,Yanwei Li,Shunhua Xiao,Renheng Wang
High-nickel ternary material is one of the most promising cathode materials with high energy density. However, this material has the disadvantages of poor cycling stability, poor thermal stability, and low safety. The synergetic effect of single crystal, element doping, and surface coating is an effective way to improve its electrochemical performance. In this work, the particle size of the single-crystal LiNi0.83Co0.11Mn0.06O2 (NCM811) material was controlled by LiCl–KCl flux, and the internal/external synergy of Ti4+ doping and LiTi2O4 coating was realized by the pretreatment of Ti(OC4H9)4 and a subsequent new temperature-changing sintering process. The single-crystal structure greatly improved the crushing of material, the Ti4+ doping effectively broadened the lattice spacing and stabilized the layered structure, and the uniform LiTi2O4 coating effectively eliminated excess lithium salts and promoted the stability of the interface structure. The electrochemical test results showed that the modified materials had excellent electrochemical properties, especially a high lithium-ion diffusion rate and high cycle stability. Therefore, it will provide a solid technical support for the synthesis of high-performance single-crystal high-nickel ternary cathode materials.
研究领域:
材料科学
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电化学
·
能源存储
✓ 已验证
DOI
高影响因子
JOURNAL OF THE EUROPEAN CERAMIC SOCIETY
·
2024
·
IF 5.8
Bei Ren,Ziqian Meng,Bixian Zhang,Sihao Jian,Chufei Cheng,Jiadong Hou,Ruixin Hao,Bo Li,Yang Miao,Chao Ma,Weihua Ji
High-entropy fluorite oxide ceramics are promising candidates for spacecraft applications due to their excellent high-temperature thermal-mechanical properties. In this work, four kinds of high-entropy fluorite oxide ceramics ((ZrHfCeYEr) (1-x)/5 Ti x )O 2-δ (HEFOs, x = 0, 0.025, 0.05, 0.075) with different Ti 4+ contents were successfully synthesized through solid-state reaction method with conventional sintering. They all exhibited phase stability when annealed at 1500 ℃ for 20 h. When the content of Ti 4+ was increased to x = 0.075, the thermal conductivity reduced to1.34 W·m −1 ·K −1 at 1100 ℃, and the hardness and elastic modulus increased to 14.01 GPa and 205.70 GPa, respectively. Furthermore, the cyclic thermal shock resistance of HEFOs at different temperatures was investigated. The initial flexural strength reached 219.03 MPa when the content of Ti 4+ was increased to x = 0.075. After 60 thermal shock cycles at 1200 ℃ and 1500 ℃, the residual strength ratios were 97.56 % and 83.36 %, respectively. The results of this study establish the foundation for future applications of high-entropy fluorite oxide ceramics in spacecraft hot-end components.
研究领域:
材料科学
·
航天工程
✓ 已验证
产品关联
DOI
高影响因子
LUMINESCENCE
·
2025
·Vol. 40
·期 7
·e70255
·
IF 3
Keyue Wu,Yi Yang,Zeya Wang
Near-infrared (NIR) phosphors activated by Cr 3+ ions hold significant potential for applications such as night vision and plant growth lighting due to their tunable emission properties governed by crystal field (CF) strength. In this study, Cr 3+ and Ti 4+ co-doped MgO phosphors were synthesized via a high-temperature solid-state reaction to modulate the NIR emission. Structural and optical characterizations revealed that Ti 4+ incorporation enhances the CF strength ( D q/ B ratio increases from 2.4 to 2.6), inducing a blue shift in the emission peak from 810 (MgO:Cr 3+ ) to 780 nm (Mg 0.8 Ti 0.2 O:Cr 3+ ) and with a strong sharp emission at 720 nm. The Ti 4+ doping also increases the fluorescence lifetime from 150.9 to 816.4 μs, attributed to altered Cr 3+ occupancy in octahedral sites and modified spin-allowed transitions. These findings demonstrate that Ti 4+ co-doping effectively tunes the NIR emission of MgO:Cr 3+ phosphors, offering a promising strategy for designing wavelength-adjustable NIR light sources.
研究领域:
材料科学
·
光学材料
·
固体物理
·
光子学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
JOURNAL OF ALLOYS AND COMPOUNDS
·
2018
·
IF 3.779
Qiannan Wu,Dedong Meng,Yu Zhang,Qidong Zhao,QiJing Bu,Dejun Wang,Xiaoxin Zou,Yanhong Lin,Shuo Li,Tengfeng Xie
Acid-treatment has been proved to be an efficient approach to improve the photoelectrochemical (PEC) performance of hematite . However, efforts to optimize hematite photoanode have been limited by an inadequate understanding of the semiconductor surface . Here we make efforts to understand the microscopic charge separation processes of Ti 4+ doped Fe 2 O 3 photoanode before and after acid-treatment. Surface photovoltage (SPV) transient and the work function measurements directly reveal that acid-treatment leads to passivation of the surface states . Surface photovoltage (SPV) spectroscopic studies coupled to open-circuit photovoltage (OPV) measurements indicate that the surface states of hematite photoanode before acid-treatment result in the pinning of the Fermi level , which reduce the intensity of interfacial electric field at the semiconductor-electrolyte interface.
研究领域:
材料科学
·
光电化学
·
能源材料
·
半导体物理
·
表面科学
·
太阳能转化
·
纳米材料
✓ 已验证
DOI
高影响因子
Journal of Advanced Ceramics
·
2022
·Vol. 11
·期 11
·1801-1814
·
IF 11.534
Cheng Fuhao,Zhang Fengnian,Liu Yufeng,Guo Meng,Cheng Chufei,Hou Jiadong,Miao Yang,Gao Feng,Wang Xiaomin
Environmental barrier coatings (EBCs) with excellent chemical resistance and good high-temperature stability are of great significance for their applications in next-generation turbine engines. In this work, a new type of high-entropy fluorite-structured oxide (Ce 0.2 Hf 0.2 Y 0.2 Pr 0.2 Gd 0.2 )O 2− δ (HEFO-1) with different Ti 4+ contents were successfully synthesized. Minor addition of Ti 4+ could be dissolved into a high-entropy lattice to maintain the structure stable, effectively reducing the phase formation temperature and promoting the shrinkage of bulk samples. Heat treatment experiments showed that all the samples remained a single phase after annealing at 1200–1600 °C for 6 h. In addition, high-entropy (Ce 0.2 Hf 0.2 Y 0.2 Pr 0.2 Gd 0.2 Ti 0.2 x )O 2− δ demonstrated great resistance to calcium—magnesium—alumina—silicate (CMAS) thermochemical corrosion. When the content of Ti was increased to x = 0.5, the average thickness of the reaction layer was about 10.5 after being corroded at 1300 °C for 10 h. This study reveals that high-entropy (Ce 0.2 Hf 0.2 Y 0.2 Pr 0.2 Gd 0.2 Ti 0.2 x )O 2− δ is expected to be a candidate for the next-generation EBC materials with graceful resistance to CMAS corrosion.
研究领域:
材料科学
·
涂层
·
高温材料
·
腐蚀抗性
✓ 已验证
产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）