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将硅纳米颗粒限域在多壳层空心球:一种提升循环稳定性的有效策略

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Science China materials 2023年第6期66卷 2199-2206页

作者：杜寰余若翰谭兴念吴劲松赵东元麦立强周亮 State Key Laboratory of Advanced Technology for Materials Synthesis and Processing Wuhan University of TechnologyWuhan 430070China International School of Materials Science and Engineering Wuhan University of TechnologyWuhan 430070China Nanostructure Research Center(NRC) Wuhan University of TechnologyWuhan 430070China Hubei Longzhong Laboratory(LZL) Wuhan University of TechnoologyXiangyang 441106China

单质硅是一种有潜力的高容量锂离子电池负极材料.然而,受限于充放电过程中巨大的体积膨胀,其循环性能并不理想.在这个工作中,我们设计了一种独特的三组分复合负极材料(Si/Cr_(2)O_(3)/C),其中Si纳米颗粒被限域在碳包覆的氧化铬多层空心... 详细信息

单质硅是一种有潜力的高容量锂离子电池负极材料.然而,受限于充放电过程中巨大的体积膨胀,其循环性能并不理想.在这个工作中,我们设计了一种独特的三组分复合负极材料(Si/Cr_(2)O_(3)/C),其中Si纳米颗粒被限域在碳包覆的氧化铬多层空心球(MSHSs)中.得益于Cr_(2)O_(3)/C基体的体积变化缓冲能力与优异的结构稳定性,将Si纳米颗粒封装在MSHSs中可以有效地提高其电化学性能.合理的结构设计赋予了Si/Cr_(2)O_(3)/C三组分复合材料高的可逆容量(在100 mA g^(-1)的电流密度下,比容量为1351 mA h g^(-1))和稳定的循环性能(在500 mA g^(-1)的电流密度下,循环300次后比容量保持在716 mA h g^(-1)).这一工作提出了一种多壳层空心结构设计的新思路,以解决硅基负极材料循环性差的瓶颈.

关键词：硅基负极材料充放电过程硅纳米颗粒循环稳定性空心结构电化学性能有效策略空心球

A new strategy to access Co/N co-doped carbon nanotubes as oxygen reduction reaction catalysts

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Chinese Chemical Letters 2021年第1期32卷 535-538页

作者： Bingshuai Liu Huang Zhou Huihui Jin Jiawei Zhu Zhe Wang Chenxi Hu Lvhan Liang Shichun Mu Daping He State Key Laboratory of Advanced Technology for Materials Synthesis and Processing Wuhan University of TechnologyWuhan 430070China Hubei Engineering Research Center of RF-Microwave Technology and Application Wuhan University of TechnologyWuhan 430070China

Carbon nanotubes(CNTs),as one-dimensional nanomaterials,show great potential in energy conversion and storage due to their efficient electrical conductivity and mass ***,the security risks,time-consuming and high cost of the preparation process hinder its further ***,we develop that a negative pressure rather than a following gas environment can promote the generation of cobalt and nitrogen co-doped CNTs(Co/N-CNTs) by using cobalt zeolitic imidazolate framework(ZIF-67) as a precursor,in which the negative pressure plays a key role in adjusting the size of cobalt nanoparticles and stimulating the rearragement of carbon atoms for forming ***,the obtained Co/N-CNTs,with high content of pyridinic nitrogen and abundant graphitized structure,exhibit superior catalytic activity for oxygen reduction reaction(ORR) with half-wave potential(E_(1/2)) of 0.85 V and durability in terms of the minimum current loss(2%) after the 30,000 s *** development provides a new pathway for large-scale and cost-effective preparation of metal-doped CNTs for various applications.

关键词： Negative pressure Cobalt zeolitic imidazolate framework Cobalt and nitrogen co-doped Carbon nanotubes Oxygen reduction reaction

Vacancy-Based Defect Regulation for High Thermoelectric Performance in Ge9Sb2Te12-x Compounds

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ACS APPLIED materials & INTERFACES 2020年第17期12卷 19664-19673页

作者： Chen, Shuo Bai, Hui Li, Junjie Pan, Wenfeng Jiang, Xianyan Li, Zhi Chen, Zhiquan Yan, Yonggao Su, Xianli Wu, Jinsong Uher, Ctirad Tang, Xinfeng State Key Laboratory of Advanced Technology for Materials Synthesis and Processing Wuhan University of Technology Wuhan 430070 China State Key Laboratory of Advanced Technology for Materials Synthesis and Processing Wuhan University of Technology Wuhan 430070 China State Key Laboratory of Advanced Technology for Materials Synthesis and Processing Wuhan University of Technology Wuhan 430070 China Hubei Nuclear Solid Physics Key Laboratory Department of Physics Wuhan University Wuhan 430072 China Hubei Nuclear Solid Physics Key Laboratory Department of Physics Wuhan University Wuhan 430072 China State Key Laboratory of Advanced Technology for Materials Synthesis and Processing Wuhan University of Technology Wuhan 430070 China Hubei Nuclear Solid Physics Key Laboratory Department of Physics Wuhan University Wuhan 430072 China State Key Laboratory of Advanced Technology for Materials Synthesis and Processing Wuhan University of Technology Wuhan 430070 China State Key Laboratory of Advanced Technology for Materials Synthesis and Processing Wuhan University of Technology Wuhan 430070 China State Key Laboratory of Advanced Technology for Materials Synthesis and Processing Wuhan University of Technology Wuhan 430070 China Department of Physics University of Michigan Ann Arbor Michigan 48109 United States State Key Laboratory of Advanced Technology for Materials Synthesis and Processing Wuhan University of Technology Wuhan 430070 China

Defect engineering is the core strategy for improving thermoelectric properties. Herein, cation doping along with modulation of cation vacancy has been developed in GeTe-based materials as an effective method to induce vacancy-based defects to boost their thermoelectric performance. A series of ternary compounds of Ge9Sb2Te12-x (x = 0, 0.03, 0.06, 0.09, 0.12, 0.15) was prepared by vacuum-melting and annealing combined with the spark plasma sintering (SPS) process. The role of Sb doping and cation vacancy on thermoelectric properties was systematically investigated. It is found that alloying Sb2Te3 into GeTe increases the concentration of cation vacancies, which is corroborated by both positron annihilation measurements and theoretical calculations. The vacancies, stacking faults, and planar defect interactions determine the thermoelectric transport properties. Adjusting the deficiency of Te effectively tunes the concentration of cation vacancies and dopant defects in the structure. In turn, this tunes the carrier concentration close to its optimum. A high power factor of 32.6 mu W cm(-1) K-2 is realized for Ge9Sb2Te11.91 at 725 K. Moreover, large strains induced by the defect structures, including Sb dopant, vacancy, staking faults, as well as planar defects intensify phonon scattering, leading to a significant decrease in the thermal conductivity from 7.6 W m(-1) K-1 for pristine GeTe to Ge9Sb2Te11.85 at room temperature. All of the above contribute to a high ZT value of 2.1 achieved for the Ge9Sb2Te11.91 sample at 775 K.

关键词： GeTe-based compounds alloying with Sb2Te3 deficiency of Te stacking fault vacancy plane thermoelectric

Ductile-Brittle Transition Mechanism of Highly-Oriented 3c-Sic in Elid

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SSRN 2024年

作者： Li, Hengyi Xu, Qingfang Zhang, Chitengfei Yang, Meijun Tu, Rong Zhang, Song Hubei Longzhong laboratory Xiangyang441000 China State Key Laboratory of Advanced Technology for Materials Synthesis and Processing Wuhan University of Technology Wuhan430070 China Wuhan University of Technology China

Compared with sintered silicon carbides (SiC), highly-orientated 3C-SiC by CVD methods boasts out-of-plane orientation uniformity, which ensures that such materials produce lower surface damage. Through the ELID grinding technique, the differences in grinding behaviors between and -orientated 3C-SiC were investigated. Both highly-orientated 3C-SiC exhibited a grinding surface where brittle and ductile removal coexisted. Specifically, brittle removal regions were observed at grain boundaries, while ductile removal regions were observed within the grains. Further indentation experiments between the two 3C-SiC show that -oriented 3C-SiC displayed a larger critical cut depth of 28.99 nm, with 1.5 times higher than that of -oriented 3C-SiC. The larger critical depth of cut contributes to more ductile removal regions with only a few brittle pits in the -oriented 3C-SiC grinding surface. In addition, the subsurface deformation of -oriented 3C-SiC was characterized by the presence of amorphous zones, dislocations and stacking faults. In contrast to the -oriented, the -oriented 3C-SiC tends to exhibit a brittle removal mode dominated by pits and cracks at the twin boundaries, as its pre-existing twins hinder the dislocation glide, resulting in stress concentration and thus forming cracks. © 2024, The Authors. All rights reserved.

关键词： Silicon carbide

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原位技术监测界面水解离

Science Bulletin 2024年第10期69卷 1355-1358页

作者：高修博李静阳晓宇 State Key Laboratory of Advanced Technology for Materials Synthesis and Processing&Shenzhen Research Institute&Laoshan Laboratory Wuhan University of TechnologyWuhan 430070China Hubei Province Key Laboratory of Coal Conversion and New Carbon Materials School of Chemistry and Chemical EngineeringWuhan University of Science and TechnologyWuhan 430081China School of Engineering and Applied Sciences Harvard UniversityCambridge MA02138USA

Most chemical and physical properties of water are related to its dynamic network of hydrogen *** between interfacial water and surfaces of solids often determine the functions and properties of natural and technological processes[1].These interactions are especially important in governing the electrocatalyst promoted hydrogen evolution reaction(HER)in water,which is an interfacial process that has particular significance in the development of hydrogen as a storable energy source.

关键词：原位技术 hydrogen 水解离

Fabrication and Property of SiC Ceramic with Large Thickness/Diameter Ratios

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Journal of Wuhan University of technology(materials Science) 2020年第3期35卷 506-513页

作者： TAN Lin HE Qianglong HU Lanxin TIAN Tian WANG Weimin State Key Laboratory of Advanced Technology for Materials Synthesis and Processing Wuhan University of TechnologyWuhan 430070China

Silicon carbide ceramics with different thicknesses/diameter ratios were prepared by using ultra-fine silicon carbide powder with the sintering additives of 1.0 wt% boron and 1.5 wt% carbon. The influence of thickness/diameter ratio on the microstructure and density of SiC ceramics was investigated in detail. The experimental results show that the addition of boron and carbon sintering aids can promote the densification process of SiC ceramic, leading to the low sintering temperature and improve mechanical properties. At 1950 ℃, SiC ceramic with a density of 99% exhibits Young's modulus, hardness, and flexural strength of 476 MPa, 28.3 GPa, and 334 MPa, respectively. It is found that long holding time has a positive effect on the uniformity of the microstructure and density distribution of SiC ceramics with large thickness/diameter ratios. Additionally, the sintering additive of boron can solid-solve into SiC, and then facilitate the phase transformation of SiC to form 6H-SiC and 4H-SiC composite ceramics.

关键词： SiC large thickness/diameter ratios mechanical properties uniformity

Taming the Anchor and Conversion of Polyselenides with a Self-Reinforcing Host in Lithium–Selenium Batteries

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SSRN 2024年

作者： Li, Hongyan Dong, Wen-Da Cao, Yueqiang Barakat, Tarek Laboureur, Marvin Ran, Mao-Jin Hu, Zhi-Yi Zhang, Hongxian Jin, Cheng-Bin Li, Yu Su, Bao-Lian College of Materials and Chemistry China Jiliang University Hangzhou310018 China University of Namur NamurB-5000 Belgium State Key Laboratory of Advanced Technology for Materials Synthesis and Processing Wuhan University of Technology Hubei Wuhan430074 China State Key Laboratory of Chemical Engineering School of Chemical Engineering East China University of Science and Technology Shanghai200237 China State Key Laboratory of Advanced Technology for Materials Synthesis and Processing China

Energy-dense lithium–selenium (Li–Se) batteries have attracted increasing attention, while their practical application is still hindered, highly relating to the volume expansion and low conductivity of Se and shuttle of Li polyselenides (LiPSes). Herein, a concurrent anchoring/converting strategy is proposed to restrain the dissolution and realize the rapid conversion of LiPSes. A prototypical regulator comprises of polar catalysts embedded in the interconnected porous muti-walled carbon network (i.e., CoSnO3 nanocubes/CNTs), which promises fast electron/ion transportation and inhibits volumetric effect. Moreover, CoSnO3 as redox accelerator promotes the bidirectional conversion of polyselenides by chemical adsorption and decreasing the reaction energy barrier. Consequently, the self-reinforcing optimized cathode exhibits superior initial capacity of 730 mAh g−1, greatly enlarged capacity after 200 cycles (increase by ~32%), and superior rate capacity (153 mAh g−1 at 2 C). This work uncovers the roles of electronic/ionic conductivity and adsorption/catalysis in Li–Se batteries, providing a guidance for taming the utilization and kinetics of cathode from material perspectives. © 2024, The Authors. All rights reserved.

关键词： Adsorption

Spallation Damage Mechanisms and Microstructural Evolution in Selective Laser Melted Ti-6al-4v Under Quasi-Isentropic Loading

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SSRN 2024年

作者： Zhang, Kaichang Li, Peibo Zhang, Yang Sun, Yi Luo, Guoqiang Shen, Qiang Hubei Longzhong Laboratory Hubei Xiangyang441000 China State Key Lab of Advanced Technology for Materials Synthesis and Processing Wuhan University of Technology Wuhan430070 China

The microstructure of additively manufactured Ti-6Al-4V significantly differs from that of traditional casting processes, and this microstructural variation directly impacts the material's mechanical properties. To ensure the safety and stability of additively manufactured Ti-6Al-4V in practical applications, this study achieves controlled dynamic loading by optimizing the cross-sectional surface density of the structural gradient flyer(SGFs). It further explores material response characteristics under varying stress and strain rates by adjusting the loading rate in spallation experiments. The initial microstructure of Ti-6Al-4V produced via selective laser melting (SLM) was investigated and analyzed. Quasi-isentropic loading experiments were conducted on 6 mm thick samples at strain rates ranging from 5.07 to 12.38 × 104 s-1. The results demonstrate that, in comparison to as-cast alloys, the SLM-processed Ti-6Al-4V alloys exhibit reduced plasticity, primarily attributed to the higher cooling rates of SLM. The alloys predominantly display brittle fracture characteristics, with distinct transgranular fracture patterns. As the loading strain rate increases, the pulse width of the loading waveform progressively narrows, spall strength markedly rises, and cracks not only propagate but also enlarge. Grain refinement was evident in both the crack extension region and along the edges, accompanied by localized stress concentration, yet no signs of recrystallization were detected. The spall strength of the material exhibited heightened sensitivity to impact stresses relative to plate impact conditions. These findings offer critical theoretical insights into the potential applications of additively manufactured titanium alloys, particularly in aerospace and defense sectors. © 2024, The Authors. All rights reserved.

关键词： Grain refinement

Locally Off-Centered Ge Atoms Contribute to High Thermoelectric Performance of Globally Averaged Cubic MnGeTe2 Alloys

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SSRN 2024年

作者： Mei, Qicai Xie, Chenghao Cui, Jingjing Liao, Chengyun Li, Songlin Tang, Xinfeng Tan, Gangjian State Key Laboratory of Advanced Technology for Materials Synthesis and Processing Wuhan University of Technology Wuhan430070 China International School of Materials Science & Engineering Wuhan University of Technology Wuhan430070 China

Exploring high-performance and environment-benign thermoelectric materials free of phase change during their service is a long-standing challenge. Herein a maximum ZT of 1.4 at 878 K is reported for non-toxic Sb-doped MnGeTe2 alloys with a consistent cubic rock salt structure above room temperature. Pristine MnGeTe2 is a heavily self-doped p-type semiconductor with its hole density (pH) exceeding 1021 cm-3. Due to the strong contribution of localized 3d orbitals from Mn to the valence band maxima lying along the Γ–K direction with a high valley degeneracy of 4 , MnGeTe2 features a superb density of states (DOS) effective mass (m* ~ 10 me), endowing it a large Seebeck coefficient of ~105 μV K-1 at 300 K despite its over high pH. Moreover, Ge atoms are locally discordant in MnGeTe2 and displaced ∼0.33 Å off the octahedron center, inducing soft polar phonons that effectively scatter the heat carrying acoustic phonons and enable a low lattice thermal conductivity (κlat ~0.57 W m-1 K-1 at 871 K). Sb doping not only efficiently neutralizes the excess pH of MnGeTe2 leading to high Seebeck coefficient (> 250 μV K-1), but further drops κlat to ~0.49 W m-1 K-1 by reinforced point defect scattering. Our work highlights the significance of local off-centering atoms in developing high-performance bulk thermoelectric materials. © 2024, The Authors. All rights reserved.

关键词： Germanium alloys