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Suppress oxygen evolution of lithium-rich manganese-based cathode materials via an integrated strategy

Green Energy & Environment 2024年第1期9卷 138-151页

作者： Wenhua Yu Yanyan Wang Aimin Wu Aikui Li Zhiwen Qiu Xufeng dong chuang dong Hao Huang Key Laboratory of Energy Materials and Devices(Liaoning Province) School of Materials Science and EngineeringDalian University of TechnologyDalian116024Liaoning ProvinceChina Dalian Engineering Research Center for New Electric Power Systerms School of Electrical EngineeringDalian University of TechnologyDalian116024Liaoning ProvinceChina

Improving the reversibility of anionic redox and inhibiting irreversible oxygen evolution are the main challenges in the application of high reversible capacity Li-rich Mn-based cathode materials.A facile synchronous lithiation strategy combining the advantages of yttrium doping and LiYO_(2) surface coating is proposed.Yttrium doping effectively suppresses the oxygen evolution during the delithiation process by increasing the energy barrier of oxygen evolution reaction through strong Y–O bond energy.LiYO_(2) nanocoating has the function of structural constraint and protection,that protecting the lattice oxygen exposed to the surface,thus avoiding irreversible oxidation.As an Li^(+) conductor,LiYO_(2) nano-coating can provide a fast Li^(+) transfer channel,which enables the sample to have excellent rate performance.The synergistic effect of Y doping and nano-LiYO_(2) coating integration suppresses the oxygen release from the surface,accelerates the diffusion of Li^(+)from electrolyte to electrode and decreases the interfacial side reactions,enabling the lithium ion batteries to obtain good electrochemical performance.The lithium-ion full cell employing the Y-1 sample(cathode)and commercial graphite(anode)exhibit an excellent specific energy density of 442.9 Wh kg^(-1) at a current density of 0.1C,with very stable safety performance,which can be used in a wide temperature range(60 to-15℃)stable operation.This result illustrates a new integration strategy for advanced cathode materials to achieve high specific energy density.

关键词： Lithium-rich manganese-based cathodes Lithium ion batteries Oxygen redox Oxygen evolution Integrated strategy

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Combined use of fly ash and silica to prevent the long-term strength retrogression of oil well cement set and cured at HPHT conditions

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Petroleum Science 2024年第2期21卷 1122-1134页

作者： Guo-dong Cheng Xue-Yu Pang Jin-Sheng Sun Zheng-Song Qiu chuang-chuang Wang Jian-Kun Qin Ning Li School of Petroleum Engineering China University of Petroleum(East China)Qingdao266580ShandongChina National Key Laboratory of Deep Oil and Gas China University of Petroleum(East China)Qingdao266580ShandongChina Oil and Gas Engineering Research Institute(Tarim Oilfield Company) China National Petroleum CorporationTarim841000XinjiangChina

The long-term strength retrogression of silica-enriched oil well cement poses a significant threat to wellbore integrity in deep and ultra-deep wells, which is a major obstacle for deep petroleum and geothermal energy development. Previous attempts to address this problem has been unsatisfactory because they can only reduce the strength decline rate. This study presents a new solution to this problem by incorporating fly ash to the traditional silica-cement systems. The influences of fly ash and silica on the strength retrogression behavior of oil well cement systems directly set and cured under the condition of 200°C and 50 MPa are investigated. Test results indicate that the slurries containing only silica or fly ash experience severe strength retrogression from 2 to 30 d curing, while the slurries containing both fly ash and silica experience strength enhancement from 2 to 90 d. The strength test results are corroborated by further evidences from permeability tests as well as microstructure analysis of set cement. Composition of set cement evaluated by quantitative X-ray diffraction analyses with partial or no known crystal structure(PONKCS) method and thermogravimetry analyses revealed that the conversion of amorphous C-(A)-S-H to crystalline phases is the primary cause of long-term strength retrogression.The addition of fly ash can reduce the initial amount of C-(A)-S-H in the set cement, and its combined use with silica can prevent the crystallization of C-(A)-S-H, which is believed to be the working mechanism of this new admixture in improving long-term strength stability of oil well cement systems.

关键词： Fly ash Long-term strength retrogression High temperature Quantitative X-ray diffraction(QXRD) Partial or no known crystal structure(PONKCS)

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Tungsten separation behavior on preparation of high-purity cerium by combined vacuum gravity sedimentation-directional solidification

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Journal of Rare Earths 2024年第6期42卷 1182-1186,I0007页

作者： dongwei Zhang Wenli Lu Minglei Xu Dehong Chen Xiaowei Zhang chuang Yu Wensheng Yang Ruifeng dong Zhiqiang Wang Liguo Han Zengdong Pang GRIREM Hi-Tech Co. Ltd.Langfang065201China National Engineering Research Center for Rare Earth China GRINM Group Co.Ltd.Beijing100088China GRIREM Advanced Materials Co. Ltd.Beijing100088China

In light of the difficult removal of harmful impurity tungsten(W)in Ce metal,in this paper a combined vacuum gravity sedimentation-directional solidification method was innovatively designed and the W separation behavior was investigated.By reducing the electron beam power instantly and gradually at reduction rates of 1,3 and 5 kW/min,it is found that W is enriched at the bottom of ingots as the melt solidifies.The enrichment effect is much better than that of single purification method and the enrichment degree increases as the beam reduction rate decreases,attributed to the k0(W)>1 andρ(W)>ρ(Ce).Overall,the minimum content of W impurity can decrease from 630 to 0.1 ppm at the top of the ingot,and the purity of Ce increases from 99.932 wt%to 99.995 wt%by this combined method.Additionally,this paper provides a new method for the removal of high density and low evaporation coefficient impurities in low vapor pressure rare earth metals.

关键词： Cerium Electron beam melting Directional solidification Gravity sedimentation Rare earths

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High-strength Ti-Al-V-Zr cast alloys designed using α and β cluster formulas

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China Foundry 2023年第1期20卷 23-28页

作者： Zhi-hao Zhu Yu-han Liu Zhi-peng Chen Tian-yu Liu Shuang Zhang Dan-dan dong chuang dong Key Laboratory for Materials Modification by Laser Ionand Electron Beams and School of Materials Science and EngineeringDalian University of TechnologyDalian 116024LiaoningChina State Key Laboratory of Light Alloy Casting Technology for High-end Equipment Shenyang Research Institute of Foundry Co.Ltd.Shenyang 110022China School of Materials Science and Engineering Dalian Jiaotong UniversityDalian 116028LiaoningChina College of Physical Science and Technology Dalian UniversityDalian 116622LiaoningChina

Ti-Al-V-Zr quaternary titanium alloys were designed followingα-{[Al-Ti12](AlTi2)}17-n+β-{[Al-Ti12Zr2](V3)}n,where n=1-7(the number ofβunits),on the basis of the dual-cluster formula of popular Ti-6Al-4V alloy.Such an alloying strategy aims at strengthening the alloy via Zr and V co-alloying in theβ-Ti unit,based on the originalβformula[Al-Ti14](V2Ti)of Ti-6Al-4V alloy.The microstructures of the as-cast alloys by copper-mold suction-casting change from pureα(n=1)toα+α’martensite(n=7).When n is 6,Ti-5.6Al-6.8V-8.1Zr alloy reaches the highest ultimate tensile strength of 1,293 MPa and yield strength of 1,097 MPa,at the expense of a low elongation of 2%,mainly due to the presence of a large amount of acicularα’martensite.Its specific strength far exceeds that of Ti-6Al-4V alloy by 35%.

关键词： titanium alloy cluster-plus-glue-atom model composition design microstructure mechanical properties

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Effect of processing parameters on formability, microstructure, and micro-hardness of a novel laser additive manufactured Ti-6.38Al-3.87V-2.43Mo alloy

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China Foundry 2022年第2期19卷 158-168页

作者： Tian-yu Liu Zhi-hao Zhu Shuang Zhang Xiao-hua Min chuang dong School of Materials Science and Engineering Dalian University of TechnologyDalian 116024LiaoningChina School of Materials Science and Engineering Dalian Jiaotong UniversityDalian 116028LiaoningChina

A novel Ti-6.38Al-3.87V-2.43Mo alloy was designed with a cluster formula of 12[Al-Ti12](V0.75Mo0.25Ti2)+4[Al-Ti12](Al3)by replacing Ti with Mo/V on the basis of the Ti-Al congruent alloy.The effects of laser power and scanning speed on the molten pool size,surface roughness,relative density,microstructure,and micro-hardness of single-track and bulk Ti-6.38Al-3.87V-2.43Mo samples prepared via laser additive manufacturing(LAM)were investigated.The results show that processing parameters significantly affect the formability,microstructure,and micro-hardness of the alloy.With decreasing laser power from 1,900 W to 1,000 W,the relative density is decreased from 99.86%to 90.91%due to the increase of lack-of-fusion;however,with increasing scanning speed,the relative density does not change significantly,but exceeds 99%.In particular,Ti-6.38Al-3.87V-2.43Mo samples of single-track and bulk exhibit a good formability under an input laser power of 1,900 W and a scanning speed of 8 mm·s_(-1),and display the lowest surface roughness(Ra=13.33μm)and the highest relative density(99.86%).Besides,the microstructure of LAM Ti-6.38Al-3.87V-2.43Mo alloy coarsens with increasing laser power or decreasing scanning speed due to the greater input energy reducing the cooling rate.The coarsening of the microstructure decreases the microhardness of the alloy.

关键词： laser additive manufacturing composition design cluster-plus-glue-atom model microstructure properties

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Composition optimization of inconel 718 via cluster formula and experimental verification

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Journal of Materials Science & Technology 2023年第9期140卷 249-259页

作者： Yancheng Li Mo Li Qing Wang Yajun Zhao Shuang Zhang Cunlei Zou Ying Li Lianchao Wang chuang dong Key Laboratory of Materials Modification by Laser Ion and Electron BeamsMinistry of EducationSchool of Materials Science and EngineeringDalian University of TechnologyDalian 116024China School of Materials Science and Engineering Dalian Jiaotong UniversityDalian 116028China dongbei Special Steel Group Co. Ltd.Dalian 116105China

Superalloys feature multi-elements and complex elemental ranges,which makes the proper composition selection difficult.In fact,more strict composition standards generally apply in practical productions.The objective of this paper is to understand and eventually to renew the composition standard via example of the most common grade Inconel 718.We have recently shown that t he alloy chemistry originates from a nearest-neighbor cluster[center-shell]plus a few next-neighbor glue atoms,or expressed in cluster for-mula[center-shell](glue atoms).By grouping the elements into Ni=(Ni,Co,Cu,Fe),Cr=(Cr,Mn,Si,Mo),and Nb=(Nb,Al,Ti),it is found that the reported alloys fall within a narrow composition zone Ni_(11.0-13.0)-Cr_(3.5-4.5)-Nb_(1) confined by cluster formulas of 16 and 18 atoms.This composition zone is also expressed in terms of 288-atom supercluster formulas,Ni_(198-208)-Cr_(63-72)-Nb_(16-18),which leads to coordi-nated elemental variations in wt.%:69.0≤Ni+Co+Cu+Fe≤72.7;19.8≤Cr+Mn+1.7 Si+0.6 Mo≤22.8;8.7≤Nb+3.2 Al+1.9 Ti≤9.8.Within this composition zone,Ni_(206)-Cr_(65.5)-Nb_(16.5) is further pinpointed and validated by our own experiments to possess the optimal match of strength and plasticity both at room and at 923 K.

关键词： Inconel 718 superalloy Cluster-plus-glue-atom model Cluster formula Composition standard

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Effect of Zr addition on the stability of precipitated Laves phase and mechanical properties of Fe–Cr–Al-based alloys at high temperatures

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Progress in Natural Science:Materials International 2022年第1期32卷 114-127页

作者： Ben Niu Zhenhua Wang Qing Wang Sen Ge chuang dong Ruiqian Zhang Huiqun Liu Peter K.Liaw Key Laboratory of Materials Modification by Laser Ion and Electron Beams (Ministry of Education) School of Materials Science and Engineering Dalian University of Technology Department of Materials Science and Engineering The University of Tennessee School of Materials Science and Engineering Central South University Science and Technology on Reactor Fuel and Materials Laboratory Nuclear Power Institute of China

The effect of a small amount of Zr addition on the temperature-dependent stability of Laves phase particles and mechanical properties of Fe-13.5Cr-4.73Al-2.07Mo-(0.34–0.5)Nb-(0.65–0.98)Ta-(0–0.33)Zr(wt. %) ferritic alloys was investigated in the present study. The designed alloy ingots were hot-rolled, aged at 1073 K for 24 h, and then re-treated at 1273 K, 1323 K, 1373 K, and 1473 K for 1 h, respectively. It was found that the Zr addition could not only stabilize the FeM Laves phase(M = Mo,Nb,Ta,Zr) to a much higher temperature, but also induce the formation of stable FeZrphase. The high-temperature(HT) microstructural stability of the alloys significantly was improved, as evidenced by the fact that a certain amount(0.66–1.19%) of precipitates(FeM, FeZr, and core(FeZr)-shell(FeM)-structured particles) with an appropriate size(～1.0 μm) uniformly distributed in the ferritic matrix even after being re-treated at 1473 K. Particularly, the formation of core-shell-structured particles at HTs was studied from the viewpoint of both solid solubility and diffusion coefficient of M in the matrix. All these aged alloys exhibited prominent mechanical properties at both room and elevated temperatures, showing high yield strength with σYS= 490–560 MPa at room-temperature and σYS= 80–85 MPa at 1073 K. The strengthening effect was further discussed in light of various strengthening mechanisms, and the calculated strength are in good agreement with the experimental results.

关键词： Fe–Cr–Al alloys Microstructural stability Phase transformation Core-shell-structured precipitates Strengthening mechanisms

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高熵陶瓷材料研究进展及挑战

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材料工程 2024年第1期52卷 83-100页

作者：王云平刘世民董闯大连交通大学材料科学与工程学院辽宁大连116028 大连大学辽宁大连116622 大连理工大学三束材料改性教育部重点实验室辽宁大连116024

高熵作为全新的材料体系,得益于巨大的组分空间、独特的微观结构以及较大的构型熵所赋予其独特且可调的优异性能,已成为材料领域的研究热点。高熵陶瓷的研究目前还处于探索阶段,尤其在精准的成分设计理论、高纯高产率粉体制备、新型烧... 详细信息

高熵作为全新的材料体系,得益于巨大的组分空间、独特的微观结构以及较大的构型熵所赋予其独特且可调的优异性能,已成为材料领域的研究热点。高熵陶瓷的研究目前还处于探索阶段,尤其在精准的成分设计理论、高纯高产率粉体制备、新型烧结工艺等方面,亟待深入研究。因此,本文针对高熵陶瓷的五大高熵效应、新的设计理论、粉体制备方法、新型烧结工艺以及综合性能与实际应用进行了梳理归纳,并通过团簇加连接原子模型(CPGA)对高熵陶瓷(HEC)成分设计进行解析,深入挖掘了HEC的组元和微结构以及性能之间的关系。未来HEC的重点发展方向仍然为基础理论设计,尤其是针对非氧化物HEC成分结构。同时,在样品制备上要在学科交叉领域寻找突破,如采用人工智能机器学习与3D打印进行制备。最后,要寻找结构、热障耐腐涂层、机械、工程光学和磁性等方面实际应用并对探究工况环境下的强化、失效机制深入探究分析。

关键词：高熵陶瓷成分设计团簇加连接原子模型(CPGA) 制备工艺性能应用

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基于最优阈值参考的瞬变电磁法小波降噪效果研究

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煤矿安全 2024年第1期55卷 185-191页

作者：董毅杨创中煤航测遥感集团有限公司陕西西安710100

瞬变电磁法野外数据采集容易受各种随机干扰影响而出现跳变现象,小波去噪通过对信号的多尺度分解、阈值设置和重构,实现对数据的降噪。为进一步提高小波去噪后的瞬变电磁法数据质量,对该过程中的阈值选择方法进行改进,提出了基于最优阈... 详细信息

瞬变电磁法野外数据采集容易受各种随机干扰影响而出现跳变现象,小波去噪通过对信号的多尺度分解、阈值设置和重构,实现对数据的降噪。为进一步提高小波去噪后的瞬变电磁法数据质量,对该过程中的阈值选择方法进行改进,提出了基于最优阈值参考的小波去噪方法;结合瞬变电磁法探测岩层富水性工程应用,对比分析不同阈值条件下的数据降噪结果,提出的算法的瞬变电磁数据实际应用效果。结果显示:提出的方法能够进一步降低感应电动势曲线在1~4 ms范围内的数值跳变现象,使数据全期衰减特性更明显。对降噪后数据的烟圈反演结果进行分析,重点解释了3处电性差异相对较大的位置,结合已知资料验证了基于最优阈值参考的小波去噪数据反演结果相对更准确。

关键词：瞬变电磁法小波去噪最优阈值感应电动势曲线烟圈反演

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CuTiNiZrV Amorphous Alloy Foils for Vacuum Brazing of TiAl Alloy to 40Cr Steel

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Journal of Materials Science & Technology 2015年第2期31卷 217-222页

作者： Honggang dong Zhonglin Yang Zengrui Wang Dewei Deng chuang dong School of Materials Science and Engineering Dalian University of Technology State Key Laboratory of Advanced Welding and Joining Harbin Institute of Technology Key Lab of Materials Modi fi cation (Dalian University of Technology) Ministry of Education

Vacuum brazing of TiAl alloy to 40Cr steel sheets was conducted with newly developed CuTiNiZrV amorphous foils. It was found that a diffusion layer,filler metal and reaction layer existed in the brazed seam. The diffusion layer in the joint brazed with Cu43.75Ti37.5Ni6.25Zr6.25V6.25(at.%) foil was flat and thin,containing Ti19Al6 and Ti2Cu intermetallic compounds; however,the diffusion layer brazed with Cu37.5Ti25Ni12.5Zr12.5V12.5 foil was uneven with bulges,consisting of essentially Ti-based solute solution. The foil with 12.5 at.% V showed inferior spreadability compared to that with 6.25 at.% V at brazing temperature. However,fracture happened along the diffusion layer with 6.25 at.% V foil due to the formation of brittle intermetallic phases,but the joints brazed with 12.5 at.% V foil failed through the TiAl substrate. These results show that designing amorphous alloy with less Ti and more V for brazing TiAl alloy to steel is appropriate.

关键词： Titanium aluminide Steel Dissimilar metal joining

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