JOURNAL OF THE EUROPEAN CERAMIC SOCIETY
·
2024
·
IF 5.8
Yuanjie Wang,Luke Ma,Xueliang Pei,Wanfeng Zhuo,Jing Huang,Qing Huang
The inevitable residual carbon that normally appears in the polycarbosilane-derived SiC ceramics has notorious effects on the crystallinity and thermal conductivity of SiC ceramic. In this study, nano Si was employed to fully exhaust unwanted residual carbon in a liquid polycarbosilane. Through addition of 12 wt% theoretical nano Si and pyrolysis to 1600 °C, the ceramic yield of the liquid polycarbosilane increased from 72.0 wt% to 81.8 wt% and the C/Si ratio of ceramic product decreased from 1.14 to 0.99. Raman spectroscopy and transmission electron microscope also confirmed that the residual carbon almost completely disappeared. In addition, the crystallization ability of SiC also improved, and as a result dramatical improvement in the thermal conductivity of SiC f /SiC composite was achieved. The reaction mechanism was investigated in detail to understand the residual carbon trapping effect of nano Si during the precursor-to-ceramic conversion.
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高影响因子
Journal of Materials Chemistry A
·
2024
·
IF 10.7
Yupeng Xiao,Tianle Li,Xiaoqian Hao,Tianjiao Zhu,Jingqi Zang,Yuqian Li,Wenju Wang
The application of Si-based anodes is mainly impeded by their intrinsic volumetric stress. Recently proposed elastic binders have been demonstrated as an efficient approach to alleviate this large stress, but the excessive dosage of binders leads to inadequate energy density. Herein, a 3D resilient ion/electron dual conductive network (LPCC) composed of carboxylic carbon nanotubes (c-CNTs) interwoven with carboxymethyl chitosan (c-CS) and lithiated poly(acrylic acid) (LiPAA) was developed. The formed covalent and hydrogen bonds can endure and dissipate volumetric stress, thereby maintaining electrode integrity. Additionally, the LPCC network intimately wraps Si–C particles and provides a continuous ion/electron dual conductive skeleton. Therefore, this novel 3D network enables Si–C anodes to deliver superior electrochemical performance even at a high Si–C content of 96 wt%. Moreover, an NCM811‖Si–C/LPCC full-cell (>3.1 mA h cm−2) achieves unprecedented high gravimetric and volumetric energy densities of 510 W h kg−1 and 1173 W h L−1, respectively. This study provides novel insights for developing efficient Si-based binders for next-generation high-energy-density systems.
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DOI
高影响因子
ADVANCED FUNCTIONAL MATERIALS
·
2025
·
IF 19
Wanping Liu,Xuelei Li,Jun Liu,Zhihui Xu,Huirong Liu,Qingwen Li,Haoxuan Liu,Hexige Wuliji,Aruuhan Bayaguud
Silicon (Si) shows excellent potential as an anode material for sulfide-based all-solid-state lithium batteries (ASSLBs). However, Si anodes face inherent challenges such as low electron conductivity and large volume changes during cycling, ultimately resulting in a short cycle life. Herein, to address these challenges, In 2 O 3 /C derived from an indium-based metal-organic framework (In-MOF) is utilized to encapsulate Si particles in situ. The Li-In alloy and Li 2 O formed in situ after the lithiation of In 2 O 3 /C provide rapid Li + transportation properties, and the existence of In 2 O 3 /C efficiently relieves the significant volume changes of Si. Consequently, the Si anode exhibits improved cyclic stability. The composite Si@In 2 O 3 /C anode prepared with a high loading of 7.64 mg cm −2 maintains a high specific capacity of 1093.2 mAh g −1 (8.36 mAh cm −2 ) after 500 cycles at 2.74 mA cm −2 , maintaining 84.3% of the initial capacity. Furthermore, a full cell prepared with a Si@In 2 O 3 /C composite anode and a LiNbO 3 -coated LiNi 0.7 Co 0.2 Mn 0.1 O 2 (LNO@NCM) cathode shows excellent cyclic stability, with 74.3% of the capacity retained after cycling 1000 times at 0.2C (0.51 mA cm −2 ) and an average Coulomb efficiency of 99.94%. This study offers a compelling idea for the design of sulfide-based ASSLB anode materials.
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高影响因子
JOURNAL OF THE AMERICAN CERAMIC SOCIETY
·
2019
·Vol. 103
·期 2
·1018-1026
·
IF 3.094
Xuefang Luo,Ziyang Hou,Tianliang Zhou,Rong-Jun Xie
Mn 4+ -activated fluoride red-emitting narrow-band phosphors have been successfully used in wide color-gamut white LEDs for liquid crystal display (LCD) backlights. However, highly concentrated and toxic HF is usually used in their synthesis, causing environment and safety issues. In this work, we proposed a HF-free green method, that is, using NH 4 F/HCl instead of HF, to synthesize a series of A 2 X F 6 :Mn 4+ ( A = K, Na, Rb, Cs; X = Si, Ge, Ti) phosphors. The microstructure, photoluminescence (PL) properties, thermal quenching, and applications of the synthesized phosphors were investigated. Using the proposed approach, the phosphors generally showed a pure phase, a particle size ranging from 5 to 45 μm, and some characteristic sharp emission lines of Mn 4+ in the red spectral range. The internal quantum efficiency was varied in a broad range of 69%-94% under the 460 nm excitation, depending on the composition of the fluoride host. Among these compositions, K 2 X F 6 :Mn 4+ ( X = Ge and Ti) phosphors even had a similar external quantum efficiency (>60%) with commercial ones. By combining K 2 GeF 6 :Mn 4+ (narrow-band red) and β -sialon:Eu 2+ (narrow-band green) with a blue LED, a white light-emitting diode (wLED) backlight with a color gamut of 87.7% National Television System Committee Standard, color temperature of 8423 K, and a luminous efficacy of 110.8 lm/W was demonstrated. These results indicate that the synthetic method proposed in this work is universal for preparing highly efficient fluoride phosphors used in wLEDs.
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高影响因子
Journal of Materials Chemistry A
·
2015
·Vol. 3
·期 48
·24437-24445
·
IF 7.443
Kai Wang,Gaofeng Teng,Jinlong Yang,Rui Tan,Yandong Duan,Jiaxin Zheng,Feng Pan
We report Sn(II) and Sn(IV) self-selective dual-doping, respectively, on Fe and Si sites of Li2FeSiO4 nanocrystals due to the steric and electronic structure effects of Sn(II,IV). Combined with experimental studies and theoretical calculations, we investigate the structure–property relationship of tin doped Li2FeSiO4 as the cathode material for high performance Li-ion batteries, in which the dual-doping enhances the electronic conductivity and lithium-ion diffusion coefficient. The doped sample with 5% Sn(IV) source shows the best electrochemical performance due to the improved electronic conductivity and Li-ion diffusivity. Density functional theory (DFT) calculations also reveal that tin dual-doped Li2FeSiO4 has better electronic conductivity and lower voltage of delithiation than that of the undoped Li2FeSiO4, which is in accordance with our experimental results.
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高影响因子
Journal of Energy Storage
·
2020
·
IF 3.762
Yuehua Weng,Guorong Chen,Fei Dou,Xianhuan Zhuang,Qiyu Wang,Mi Lu,Liyi Shi,Dengsong Zhang
Silicon (Si) attracts attention for its ultra-high theoretical specific capacity (3579 mAh g −1 ) as anodes for lithium-ion batteries (LIB). However, adjusting the contradiction between long life and volume expansion has always been a great challenge for Si-based anodes. In this work, we designed a mulberry-like Si-based anode material (p-SiO x /SiC@C) by an in situ self-assembly and magnesium reduction approach. The most outstanding advantage of this strategy is the formation of silicon carbide (SiC) interlayer between SiO x and carbon coating, which hinders the further reduction of SiO x and realizes controllable specific capacity. The SiC interlayer on the SiO x surface can effectively prevent the electrolyte from penetrating and stabilize the solid electrolyte interphase (SEI) well. As a result, p-SiO x /SiC@C shows stable Li + storage performance and ultra-long cycle stability. Even after 2000 cycles under 2.0 A g −1 , p-SiO x /SiC@C still maintains a complete morphology; the capacity retention rate is about 79%; the capacity loss rate is only 0.01% per cycle on average; and it is even more gratifying that the average coulombic efficiency reaches 99.7%. This work opens up a new direction for the practical application of Si-based anode materials.
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高影响因子
JOURNAL OF THE EUROPEAN CERAMIC SOCIETY
·
2024
·
IF 5.8
Lin Cao,Yuanyuan Wang,Xueqing Yu,Zhilun Lu,Ge Wang,Minmin Mao,Bing Liu,Lei Cao,Hadi Barzegar Bafrooei,Matjaz Spreitzer,Dawei Wang,Kaixin Song
Ultra-low permittivity ( ε r ：4–5) Mg 2 Al 4– x (Ge 0.5 Mg 0.5 ) x Si 5 O 18 (0.12 ≤ x ≤ 0.28) and Mg 2 Al 4– y (Mn 0.5 Mg 0.5 ) y Si 5 O 18 (0.1 ≤ y ≤ 0.3) cordierite ceramics were fabricated by solid-state reaction method. The improvement in [(Si 4 Al 2 )O 18 ] hexahedral ring roundness significantly enhances the quality factor through the substitution of complex ionic pairs of Ge 0.5 Mg 0.5 /Mn 0.5 Mg 0.5 for Al lattice sites in the [(Si 4 Al 2 )O 18 ] hexahedral ring of these cordierite ceramics. Excellent microwave dielectric performances of Mg 2 Al 3.8 (Ge 0.5 Mg 0.5 ) 0.2 Si 5 O 18 and Mg 2 Al 3.8 (Mn 0.5 Mg 0.5 ) 0.2 Si 5 O 18 ceramics sintered at 1400 °C were demonstrated using the Hakki-Coleman resonant method with ε r = 4.676, Q×f = 186, 503 [email protected] GHz and 199,476 GHz @ 27.434 GHz, τ f = −20.02 ppm/°C and ε r = 4.807, Q×f = 101,420 [email protected] GHz and 143,005 GHz @ 27.366 GHz, τ f = −26.44 ppm/°C, respectively. These results present the potential application of high-quality cordierite in future B5G/6 G millimeter and terahertz communication frequency bands.
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高影响因子
AIP Advances
·
2022
·Vol. 12
·期 5
·
IF 1.697
Tu Huan,Zhao Guoying,Hou Jingshan,Liu Yufeng,Zhou Yan,Zhang Ganghua,Sun Hong-Tao,Li Ji-Guang,Fang Yongzheng
White light emitting diodes (LEDs) suffer from two most common drawbacks: the deficiency of the red component and the poor thermal stability of silicone. Ce 3+ -doped garnet phosphors with tailor-made luminescence properties can be achieved by variations in {A}, {B}, and {C} cation sites. Herein, a simultaneous ion co-substitution design strategy has been adopted to synthesize a series of (Y, Ca) 3 (Al, Mg) 2 (Al, Si) 3 O 12 garnet phosphors and corresponding phosphor-in-glass (PiG) films. The co-substitution is finely restricted to the assigned sites. The emission peak is shifted from 529 to 565 nm, which is beneficial to obtain low color temperatures and high color rendering using a single phosphor for white LEDs. By employing the as-synthesized phosphor, the corresponding PiG films were fabricated by the low temperature co-sintering technology using the SiO 2 –B 2 O 3 –ZnO–Na 2 O glass system characterized with excellent thermal stability and moisture resistance. The morphological and elemental analyses demonstrated that the as-made phosphor powders were uniformly distributed in the glass host without any interfacial reactions. Finally, modular white LEDs with a high color rendering (Ra = 82.7) is achieved through the as-synthesized PiG film on an InGaN blue chip. This study may open up a facile approach to obtain high quality luminescence based on the mono-luminescence center, avoiding excitation energy wastage and low quantum efficiency aroused by multi-luminescence centers or color compensation phosphors in glass.
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高影响因子
Journal of Materials Chemistry A
·
2017
·Vol. 5
·期 15
·7026-7034
·
IF 8.867
Min Zhu,Jie Yang,Zhihao Yu,Haibiao Chen,Feng Pan
Silicon (Si) is a promising anode material for lithium-ion batteries (LIBs) owing to its very high lithium storage capacity; however, fragmentation of Si caused by drastic volume change during lithium insertion and extraction leads to serious capacity decay during cycling. In this work, we report a novel method to synthesize an in situ nanocomposite containing Si nanoparticles evenly embedded in an electrically conductive SiOx@C network (Si/SiOx@C) from one single polysiloxane precursor. In our process, Si nanocrystals were reduced from the polysiloxane precursor using a low temperature molten salt reduction method, and carbon segregated out in the SiOx@C phase which evolved during the subsequent pyrolysis. As an anode material for LIBs, the Si/SiOx@C nanocomposite showed a specific capacity up to 1292 mA h g−1 at a current density of 0.4 A g−1 and 81.84% capacity retention after 200 cycles. The high capacity and stable performance of Si/SiOx@C as an anode material can be attributed to the continuous SiOx@C matrix which provides reliable mechanical support, electronic and ionic conductivity, and a stable solid–electrolyte interphase (SEI). This work demonstrated the viability of deriving a homogenous nanocomposite from a single polymeric precursor, which creates a promising anode material for next-generation LIBs.
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高影响因子
ACS Applied Energy Materials
·
2024
·
IF 5.4
Chunbo Yang,Xiang Yan,Weiwei Gao,Yang Xia,Hongjie Liu,Liuyi Hu,Wenlong Song,Wenkui Zhang,Xinhui Xia,Hui Huang
Two-dimensional (2D) silicon nanomaterial is a promising anode for lithium-ion batteries (LIBs) due to its large specific area, short ion transport path, and minimized volume expansion. However, its batch utilization is greatly limited by complicated synthesis procedures and time or energy consumption. Herein, we report a facile strategy to construct a kind of Si@C–Fe3O4 lamellar composite with enhanced performance as a LIB anode material. The 2D Si nanosheets are thermally exfoliated from the layered Zintl compound CaSi2 reacting with CO2, followed by surface coating of the C–Fe3O4 layer via the decomposition of ferrocene. Throughout 100 cycles, the as-synthesized Si@C–Fe3O4 composite maintains a stable specific capacity of 1000 mA h g–1 at 0.2 A g–1 with a subtle decay. Compared to 2D Si nanosheets, the composite exhibits better specific capacity and rate capability, particularly at high rates. It is found that C–Fe3O4 is an efficient and low-cost component for enhancing the lithium storage capability of Si-based anodes. We expect that this study will provide a simple and scalable path to the practical fabrication of Si-based anodes toward high-performance LIBs.
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高影响因子
JOURNAL OF SOLID STATE ELECTROCHEMISTRY
·
2023
·Vol. 27
·期 5
·1165-1175
·
IF 2.5
Liu Shuling,Zhang Wei,An Yiming,Li Ying,Wang Jie,Wang Chao
The Si-based flexible electrodes attracted increasing research interests owing to the growing demand for high-performance flexible energy storage devices. Herein, a facile and smart self-assembly strategy is adopted to address huge volume expansion and particle aggregation issues of Si-based anodes, and a high-performance freestanding film anode (NC@Si/CNTs/N-rGO) is synthesized. The 3D-crosslinked porous graphene-CNTs networks offer abundant electric conductive pathways, high active sites, large internal space to accommodate the expansion of Si NPs, and facilitate Li + diffusion and insertion/extraction kinetics. The synergistic effect between the well-dispersed Si/NC nanoparticles and 3D porous networks significantly enhances electrochemical performance of Si NPs. The as-prepared NC@Si/CNTs/N-rGO electrode exhibits a high reversible specific capacity of 1089 mAh·g −1 at a charge–discharge current density of 1 A·g −1 after 500 cycles. Even at 2 A·g −1 , the electrode still exhibits an excellent reversible specific capacity of 606 mAh·g −1 after 300 cycles. These indicate that the NC@Si/CNTs/N-rGO is a promising candidate for high-performance flexible anode material in lithium-ion batteries.
研究领域:
材料科学
·
电化学
·
纳米科技
·
能源存储
·
先进电池技术
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DOI
高影响因子
ANALYTICA CHIMICA ACTA
·
2020
·
IF 5.977
Xuelin Dong,Yuxiang Xiong,Nan Wang,Zhou Song,Jie Yang,Xiumei Qiu,Lihua Zhu
The analysis of siliceous matrix samples may adopt a two-step pretreatment , which includes melting with ammonium hydrogen fluoride and redissolving with nitric acid . However, the residual of substrate silicon unfavorable to the determination of trace elements in the samples due to serious matrix effects. Here, a new digestion method using simultaneously both ammonium bifluoride and nitric acid under normal pressure was developed for high-purity quartz sand sample. The digestion pretreatment is a two step process: melting/dissolving with both ammonium bifluoride and nitric acid at 200 °C for 2 h, and evaporating the solution at 250 °C to dryness. As confirmed by XRD analysis, silicates in the sample were converted to (NH 4 ) 3 SiF 6 NO 3 in the melting/dissolving step. TGA analysis shows that the generated (NH 4 ) 3 SiF 6 NO 3 could be decomposed and evaporated completely at 250 °C, which ensured a complete removal of silicon by the followed evaporation of the solution at 250 °C. As a result, the followed ICP-OES and ICP-MS analysis needed a solution dilution of only 100 times for the determination of Ca, Mg, Al, Rb, Ba, REE and other trace elements. The new method was applied to the analysis of three certified reference materials, and the results were well consistent with the standard value with RSD% values between 0.62% and 9.73%. Therefore, this method can be applied to the analysis of trace elements in high purity silica-based samples, with the advantages of time-saving, small dilution factor (only 100 times) and low detection limit.
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PubMed
高影响因子
危险品化学品经营许可证（带存储）