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Realizing high-performance Na_(3)V_(2)(PO_(4))_(2)O_(2)F cathode for sodium-ion batteries via Nb-Doping

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矿物冶金与材料学报:英文版 2023年第10期30卷 1859-1867页

作者： Jie Wang Yifeng Yuan Xianhui Rao Min’an Yang Doudou Wang Ailing Zhang Yan Chen Zhaolin Li Hailei Zhao School of Materials Science and Engineering University of Science and Technology BeijingBeijing 100083China Beijing Municipal Key Lab of Advanced Energy Materials and Technologies Beijing 100083China

Na_(3)V_(2)(PO_(4))_(2)O_(2)F(NVPOF)has received considerable interest as a promising cathode material for sodium-ion batteries because of its high working voltage and good structural/thermal stability.However,the sluggish electrode reaction resulting from its low intrinsic electronic conductivity significantly restricts its electrochemical performance and thus its practical application.Herein,Nb-doped Na_(3)V_(2-x)Nb_(x)(PO_(4))_(2)O_(2)F/graphene(rGO)composites(x=0,0.05,0.1)were prepared using a solvothermal method followed by calcination.Compared to the un-doped NVPOF/r GO,Doping V-site with high-valence Nb element(Nb^(5+))(Na_(3)V_(1.95)Nb_(0.05)(PO_(4))_(2)O_(2)F/r GO(NVN05POF/rGO))can result in the generated V4^(+)/V3^(+)mixed-valence,ensuring the lower bandgap and thus the increased intrinsic electronic conductivity.Besides,the expanded lattice space favors the Na^(+)migration.With the structure feature where NVN05POF particles are attached to the rGO sheets,the electrode reaction kinetics is further accelerated owing to the well-constructed electron conductive network.As a consequence,the as-prepared NVN05POF/r GO sample exhibits a high specific capacity of~72 m Ah·g^(-1)at 10C(capacity retention of 65.2%(vs.0.5C))and excellent long-term cycling stability with the capacity fading rate of~0.099%per cycle in 500 cycles at 5C.

关键词： sodium vanadium fluorophosphate cathode Doping rate capability sodium-ion batteries

Architecture modification and In^(3+)-Doping of WO_(3) photoanodes to boost the photoelectrochemical water oxidation performance

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Science China Chemistry 2023年第11期66卷 3269-3279页

作者： Peng Zeng Yang Zhou Lingling Peng Shaochuan Wang Tianyou Peng School of Food and Pharmaceutical Engineering Zhaoqing UniversityZhaoqing 526061China College of Chemistry and Molecular Sciences Wuhan UniversityWuhan 430072China

WO_(3) photoanodes have been widely utilized for the oxygen evolution reaction(OER)in the photoelectrochemical water splitting system.Herein,the effects of hydrazine hydrate modification and In^(3+)-Doping on the physicochemical properties and photocurrent density of the WO_(3) photoanode prepared by hydrothermally treating at 160℃followed by calcining at 500℃are investigated.Among them,the hydrazine hydrate in the hydrothermal solution can serve as a texture regulator,resulting in the formation of WO_(3) films with the layered architecture stacked by nanosheets dominantly exposed(020)facets,which allows the WO_(3) films to have faster charge separation and larger specific surface area for OER according to the characterization results of microstructures and photoelectrochemcial behaviors;while the In^(3+)-Doping can optimize the energy band structure of WO_(3) and adjust the work function to increase the driving force of OER based on the ultraviolet photoelectron spectroscopy,Mott–Schottky and open-circuit photovoltage plots.Under the simulated sunlight(AM1.5G)illumination,the designed In^(3+)–WO_(3)(N_2H_4)photoanode in Na_2SO_4 solution delivers amaximum incident photon-to-current efficiency of 38.6%at 410 nm and a photocurrent density of 1.93 mA cm^(-2)at 1.23 V vs.RHE,which is 2.8 and 3.0 times higher than the pristine WO_(3) photoanode,respectively.This study provides a promising strategy to improve the water splitting performance of nanostructured WO_(3) photoanodes by altering the architecture and introducing heteroatoms.

关键词： WO_(3)photoanode oxygen evolution reaction photoelectrochemical water splitting Doping architecture modification

Effect of different Doping elements on performance of Ce-Mn/TiO_(2)catalyst for low temperature denitration

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Journal of Rare Earths 2023年第5期41卷 689-697,I0002页

作者： Lihua Huang Jian Hua Insititute of Environment and Resources Southwest University of Science and TechnologyMianyang 621010China National Engineering Research Center for Flue Gas Desulfurization Chengdu 610065China

Sm and Ho were doped in Ce-Mn/TiO_(2)catalyst respectively to enhance its denitration performance at low temperature.X-ray diffraction(XRD),N2adsorption-desorption,X-ray photoelectron spectroscopy(XPS),NH3-temperature programmed desorption(NH3-TPD),H2-temperature programmed reduction(H2-TPR)and in situ diffuse reflectance infrared Fourier transform spectroscopy(DRIFTS)techniques were used to analyze the structure and performance of catalysts.The results demonstrate that Ho Doping increases the amount of acid sites and improves low temperature redox property of Ce-Mn/TiO_(2),which lead to excellent DeNOxperformance of Ho-Ce-Mn/TiO_(2)in the whole reaction temperature range.Sm Doping results in decline of redox property,but it is beneficial to increasing the acid sites of Ce-Mn/TiO_(2).The increased surface acid sites and moderate oxidative ability impart Sm-Ce-Mn/TiO_(2)higher denitration activity and N2selectivity at temperature above 150℃.Lewis acid sites and redox property are the main factors affecting the activity of catalysts.Doping of Ho and Sm both improves sulfur resistance performance of Ce-Mn/TiO_(2)by inhibiting the adsorption of SO_(2)and formation of sulfate.Ce-Mn/TiO_(2)modified by Ho shows better sulfur resistance than that doped with Sm because of its more surface acid sites.

关键词： Ce-Mn/TiO_(2)catalyst Doping Sm Ho Denitration performance Rareearths

Donor-acceptor conjugated copolymer with high thermoelectric performance:A case study of the oxidation process within chemical Doping

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Chinese Physics B 2022年第2期31卷 80-88页

作者：陈凉君王维肖生强唐新峰 State Key Laboratory of Advanced Technology for Materials Synthesis and Processing Wuhan University of TechnologyWuhan 430070China

The Doping process and thermoelectric properties of donor-acceptor(D-A)type copolymers are investigated with the representative poly([2,6-4,8-di(5-ethylhexylthienyl)benzo[1,2-b;3,3-b]dithiophene]3-fluoro-2-[(2-ethylhexyl)-carbonyl]thieno[3,4-b]thiophenediyl))(PTB7-Th).The PTB7-Th is doped by Fe Cl;and only polarons are induced in its doped films.The results reveal that the electron-rich donor units within PTB7-Th lose electrons preferentially at the initial stage of the oxidation and then the acceptor units begin to be oxidized at a high Doping concentration.The energy levels of polarons and the Fermi level of the doped PTB7-Th remain almost unchange with different Doping levels.However,the morphology of the PTB7-Th films could be deteriorated as the Doping levels are improved,which is one of the main reasons for the decrease of electrical conductivity at the later stage of Doping.The best electrical conductivity and power factor are obtained to be 42.3 S·cm^(-1);and 33.9μW·mK^(-1),respectively,in the doped PTB7-Th film at room temperature.The power factor is further improved to 38.3μW·mK^(-1);at 75℃.This work may provide meaningful experience for development of D-A type thermoelectric copolymers and may further improve the Doping efficiency.

关键词： donor-acceptor copolymer Doping oxidization process thermoelectric performance

Flash-assisted Doping graphene for ultrafast potassium transport

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Nano Research 2022年第5期15卷 4083-4090页

作者： Yongzhi Zhang Xianjue Chen Wanglai Cen Wenhao Ren Haocheng Guo Sicheng Wu Yang Xiao Sheng Chen Yong Guo Dan Xiao Chuan Zhao Institute of New Energy and Low-Carbon Technology(INELT) Sichuan UniversityChengdu 610065China School of Chemistry University of New South WalesSydney 2052Australia College of Chemistry Sichuan UniversityChengdu 610064China

Graphene has been widely used for electrical energy storage and its performances could be further improved by heteroatom Doping.How to prepare doped graphene efficiently and economically remains a significant challenge.Here,we propose a flash-assisted Doping method to produce nitrogen-and sulfur-doped graphene(N-rGO and S-rGO).Using this method,graphene oxide(GO)is reduced to few-layer graphene(rGO)in seconds without the use of reductants,accompanied with a high Doping efficiency.Particularly,the as-synthesized N-rGO with a high N content of 12.75 at.%used as potassium-ion battery(KIB)anode exhibits ultrafast K+-transport kinetics and superior K^(+)-storage capability.Quantitative kinetics analysis and theoretical simulation are used to reveal the mechanism of transportation and storage of K^(+)in N-rGO.

关键词： graphene Doping flash anodes potassium-ionbatteries

非均相掺杂诱导表面形貌重构构建高性能LiNiO_(2)正极材料用于锂离子电池

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Science China Materials 2023年第7期66卷 2582-2590页

作者：张宇栋丁国彧李金翰刘九鼎黄赛芳程方益 School of Materials Science and Engineering Jiangsu University of Science and TechnologyZhenjiang 212100China Key Laboratory of Advanced Energy Materials Chemistry(Ministry of Education) Nankai UniversityTianjin 300071China

具有高容量的LiNiO_(2)(LNO)是高能锂离子电池最受欢迎的正极材料之一,但是其存在结构和界面稳定性差,循环性能不理想等问题.常规Mg、Al元素掺杂可有效改善稳定性,但会导致可逆容量及倍率性能的损失.本文通过分段的共沉淀法制备了铝镁... 详细信息

具有高容量的LiNiO_(2)(LNO)是高能锂离子电池最受欢迎的正极材料之一,但是其存在结构和界面稳定性差,循环性能不理想等问题.常规Mg、Al元素掺杂可有效改善稳定性,但会导致可逆容量及倍率性能的损失.本文通过分段的共沉淀法制备了铝镁不均匀掺杂的LNO二次球形前驱体,利用不均匀掺杂减少了掺杂剂用量并诱导实现了前驱体表面形貌的重构,煅烧后形成具有疏松多孔表层形貌的二次颗粒.改性后的LNO正极具有良好的循环稳定性(全电池150次循环后容量保持率为95.1%)和大倍率放电能力(10 C时达到177.9 mA h g^(-1)),这是由于比表面积的增加促进了锂离子传输,以及镁、铝的掺杂缓解了LNO循环过程中的有害相变.该工作揭示了通过设计掺杂元素的分布可以有效地调节LNO的形貌、结构和性能,为合成高性能的LNO正极材料提供了新的策略.

关键词： LiNiO_(2) lithium-ion battery cobalt-free cathode Doping core/shell microstructure

拓扑半金属Mo_(5)Si_(3)中磷掺杂诱导T_(c)~10.8 K的强耦合超导电性

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Science China Materials 2022年第11期65卷 3125-3133页

作者：阮彬彬孙俊男陈银杨清松赵康周孟虎谷亚东马明伟陈根富单磊任治安 Institute of Physics and Beijing National Laboratory for Condensed Matter Physics Chinese Academy of SciencesBeijing 100190China Information Materials and Intelligent Sensing Laboratory of Anhui Province Institutes of Physical Science and Information TechnologyAnhui UniversityHefei 230601China Key Laboratory of Structure and Functional Regulation of Hybrid Materials(Anhui University) Ministry of EducationHefei 230601China School of Materials Science and Engineering University of Science and Technology BeijingBeijing 100083China School of Physical Sciences University of Chinese Academy of SciencesBeijing 100049China Pilot National Laboratory for Marine Science and Technology Qingdao 266237China Songshan Lake Materials Laboratory Dongguan 523808China

通过对拓扑半金属Mo_(5)Si_(3)的硅位进行磷掺杂,我们发现了Mo_(5)Si_(3-x)P_(x)(0.5≤x≤2.0)中强耦合的超导电性.W_(5)Si_(3)结构的Mo_(5)Si_(3)本身并不具有超导性,随着磷掺杂的增加,其晶格常数a单调减小,而c单调增加.在Mo_(5)Si_(3-x)P_(x)(0.5≤x≤2.0)中,电阻、磁化率和比热测量揭示了其中的体超导特性.Mo_(5)Si_(1.5)P_(1.5)的超导转变温度(T_(c))高达10.8K,创造了W_(5)Si_(3)结构超导体的T_(c)纪录,其上下临界场分别为14.56 T和105 mT,且是一个具有强电子-声子耦合的全能隙超导体.第一性原理计算表明,强的电子-声子耦合可能来自于掺磷所引起的费米面的移动,同时也揭示了Mo_(5)Si_(3)非平庸的能带拓扑性质.Mo_(5)Si_(3-x)P_(x)超导体的T_(c)和上临界场在准二元化合物中相当高,超过了NbTi超导体,具有潜在的应用价值.本文的结果表明W_(5)Si_(3)型结构中可能存在更多的新型超导体,对该体系的研究将有助于拓扑超导体的发现.

关键词： Mo_(5)Si_(3) superconductivity Doping topological insulator electron-phonon coupling

Tailoring thermal stability of ceria-zirconia mixed oxide by Doping of rare earth elements:From theory to experiment

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Journal of Rare Earths 2022年第8期40卷 1272-1280页

作者： Zheng Zhao Xiaowei Huang Yongqi Zhang Juanyu Yang Meisheng Cui Yongke Hou Zongyu Feng National Engineering Research Center for Rare Earth Materials GRINM Group Corporation LimitedBeijing 100088China Griem Hi-tech Co. Ltd.Langfang 065000China Rare Earth Functional Materials(Xiong’an)Innovation Center Co. Ltd.Baoding 071700China

Ceria-zirconia mixed oxides(CZMO)are widely used in many important catalysis fields.However,pure CZMO is known to have poor thermal stability.In this paper,a strategy was proposed to design Ce_(0.475)Zr_(0.475)M_(0.05)O_(2)(M=La,Y,Pr,Nd,Pm,Sm,Eu,Gd,Tb,Er,Lu,and,Yb)oxide surface with high thermal stability by using first-principles molecular dynamics(FPMD)simulation and experiment method.Through the structure stability analysis at different temperatures,the surface energyγas a function of R_(ion)/D_(ave)is identified as a quantitative structure descriptor for analyzing the Doping effect of rare earth(RE)elements on the thermal stability of Ce_(0.475)Zr_(0.475)M_(0.05)O_(2).By Doping the suitable RE,γcan be adjusted to the optimal range to enhance the thermal stability of Ce_(0.475)Zr_(0.475)M_(0.05)O_(2).With this strategy,it can be predicted that the sequence of thermal stability improvement is Y>La>Gd>Nd>Pr>Pm>Sm>Eu>Tb>Er>Yb>Lu,which was further verified by our experiment results.After thermal treatment at 1100℃for 10 h,the specific surface area(SSA)of aged Y-CZ and La-CZ samples can reach 21.34 and 19.51 m~2/g,which is 63.02%and 49.04%higher than the CZMO sample without Doping because the surface Doping of Y and La is in favor of inhibiting the surface atoms thermal displacement.In a word,the strategy proposed in this work can be expected to provide a viable way for designing the highly efficient CZMO materials in extensive applications and promoting the usages of the high-abundance rare-earth elements Y and La.

关键词： Cerium zirconium oxides surface Thermal stability Doping Structure descriptor Rare earth metals Theory and experiment

Doping induced morphology,crystal structure,and upconversion luminescence evolution:from Na_(3)ScF_(6):Yb/Er/Y to NaYF_(4):Yb/Er/Sc nanocrystals

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Rare Metals 2023年第3期42卷 1018-1027页

作者： Miao-Miao Liu Guang-Chao Zheng Yang Wei Dan Tian Qing-Bo Zheng Ling Huang Juan Xie School of Physics and Microelectronics Zhengzhou UniversityZhengzhou 450001China Key Laboratory of Flexible Electronics(KLOFE)and Institute of Advanced Materials(IAM) Jiangsu National Synergetic Innovation Center for Advanced Materials(SICAM)Nanjing Tech University(NanjingTech)Nanjing 211816China College of Materials Science and Engineering Nanjing Forestry UniversityNanjing 210037China

Impurity Doping not only provides a fundamental approach to impart unique electronic,magnetic and optical properties to target nanomaterials,but also has critical influence on nucleation and growth of many functional nanocrystals.In the current study,Y^(3+)and Sc^(3+)were adopted to tune the shape,size,and upconversion luminescence properties of Na_(3)ScF_(6):Yb/Er and NaYF_(4):Yb/Er samples,respectively.When Y^(3+)Doping concentration was lower than 10 mol%,the size and shape of Na_(3)ScF_(6):Yb/Er(18/2)nanoparticles gradually changed from~18 nm rhombus to 36 nm spheres.Subsequently,the coexistence of Na_(3)ScF_(6):Yb/Er and NaYF_(4):Yb/Er nanoparticles was observed during 20 mol%-50 mol%Y^(3+)Doping,and finally NaYF_(4):Yb/Er nanoparticles became the only product at>60 mol%Y^(3+)Doping where the role of Sc^(3+)turned into dopant and the size of nanocrystals decreased from~30 to 20 nm gradually.Both Y^(3+)and Sc^(3+)ions Doping could enhance the upconversion luminescence intensity of Na_(3)ScF_(6):Yb/Er and NaYF_(4):Yb/Er samples,for which possible mechanism was proposed from the perspective of crystal structure.Finally,the upconversion luminescence details were disclosed.

关键词： Doping Crystal growth Controlled synthesis Upconversion