Research progress on vanadium oxides for potassium-ion batteries

Potassium-ion batteries(PIBs)have been considered as promising candidates in the post-lithium-ion battery era.Till now,a large number of materials have been used as electrode materials for PIBs,among which vanadium oxides exhibit great potentiality.Vanadium oxides can provide multiple electron transfers during electrochemical reactions because vanadium possesses a variety of oxidation states.Meanwhile,their relatively low cost and superior material,structural,and physicochemical properties endow them with strong competitiveness.Although some inspiring research results have been achieved,many issues and challenges remain to be further addressed.Herein,we systematically summarize the research progress of vanadium oxides for PIBs.Then,feasible improvement strategies for the material properties and electrochemical performance are introduced.Finally,the existing challenges and perspectives are discussed with a view to promoting the development of vanadium oxides and accelerating their practical applications.

Two-dimensional organic cathode materials for alkali-metal-ion batteries

With the increasing demand for large-scale battery systems in electric vehicles(EVs) and smart renewable energy grids, organic materials including small molecules and polymers utilized as electrodes in rechargeable batteries have received increasing attraction. In recent years, two-dimensional(2D) organic materials possessing planar layered architecture exhibit optional chemical modification, high specific surface area as well as unique electrical/magnetic properties, which have been emerging as the promising functional materials for wide applications in optoelectronics, catalysis, sensing, etc. Integrating with high-density redox-active sites and hierarchical porous structure, significant achievements in 2D organic materials as cathode materials for alkali-metal-ion batteries have been witnessed. In this review, the recent progress in synthetic approaches, structure analyses, electrochemical characterizations of 2D organic materials as well as their application in alkali-metal-ion batteries containing lithium ion battery(LIB), lithium sulfur battery(LSB), lithium air battery(LAB) and sodium ion battery(SIB) are summarized systematically,and their current challenges including cycling stability and electron conductivity for cathode materials in battery fields are also discussed.

Hollow Bio-derived Polymer Nanospheres with Ordered Mesopores for Sodium-Ion Battery

Bio-inspired hierarchical self-assembly provides elegant and powerful bottom-up strategies for the creation of complex materials.However,the current self-assembly approaches for natural bio-compounds often result in materials with limited diversity and complexity in architecture as well as microstructure.Here,we develop a novel coordination polymerization-driven hierarchical assembly of micelle strategy,using phytic acid-based natural compounds as an example,for the spatially controlled fabrication of metal coordination bio-derived polymers.The resultant ferric phytate polymer nanospheres feature hollow architecture,ordered meso-channels of^12 nm,high surface area of 401 m2 g−1,and large pore volume of 0.53 cm3 g−1.As an advanced anode material,this bio-derivative polymer delivers a remarkable reversible capacity of 540 mAh g−1 at 50 mA g−1,good rate capability,and cycling stability for sodium-ion batteries.This study holds great potential of the design of new complex bio-materials with supramolecular chemistry.

The key challenges and future opportunities of electrochemical capacitors

Electrochemical capacitors(ECs)with unique merits of fast charge/discharge rate and long cyclability are one of the representative electrochemical energy storage systems,possessing wide applications in power electronics and automotive transportation,etc.[1,2].Furthermore.

NBN-doped nanographene embedded with five-and seven-membered rings on Au(111)surface

Nanographenes(NGs)can be embedded with predesigned dopants or nonhexagonal rings to tailor the electronic properties and provide ideal platforms to study the unique physical and chemical properties.Here,we report the on-surface synthesis of NBN-doped NG embedded with five-and seven-membered rings(NBN-575-NG)on Au(111)from a oligophenylene precursor preinstalled with a NBN unit and a heptagonal ring.Scanning tunneling microscopy and non-contact atomic force microscopy images elucidate the intramolecular cyclodehydrogenation and the existence of the five-and seven-membered rings.Scanning tunneling spectroscopy spectra reveal that the NBN-575-NG is a semiconductor,which agrees with the density functional theory calculation results on a freestanding NBN-575-NG with the same structure.This work provides a feasible approach for the on-surface synthesis of novel NGs containing non-hexagonal rings.

Fabrication of sulfur-doped cove-edged graphene nanoribbons on Au(111)

The on-surface synthesis from predesigned organic precursors can yield graphene nanoribbons(GNRs)with atomically precise widths,edge terminations and dopants,which facilitate the tunning of their electronic structures.Here,we report the synthesis of novel sulfur-doped cove-edged GNRs(S-CGNRs)on Au(111)from a specifically designed precursor containing thiophene rings.Scanning tunneling microscopy and non-contact atomic force microscopy measurements elucidate the formation of S-CGNRs through subsequent polymerization and cyclodehydrogenation,which further result in crosslinked branched structures.Scanning tunneling spectroscopy results reveal the conduction band minimum of the S-CGNR locates at 1.2 e V.First-principles calculations show that the S-CGNR possesses an energy bandgap of 1.17 e V,which is evidently smaller than that of an undoped cove-edged GNR(1.7 e V),suggesting effective tuning of the bandgap by introducing sulfur atoms.Further increasing the coverage of precursors close to a monolayer results in the formation of linear-shaped S-CGNRs.The fabrication of S-CGNRs provides one more candidate in the GNR toolbox and promotes the future applications of heteroatom-doped graphene nanostructures.

Ligand centered electrocatalytic efficient CO_(2) reduction reaction at low overpotential on single-atom Ni regulated molecular catalyst

Electrochemical CO_(2) reduction reaction(CO_(2)RR)into value-added chemicals/fuels is crucial for realizing the sustainable carbon cycle while mitigating the energy crisis.However,it is impeded by the relatively high overpotential and low energy efficiency due to the lack of efficient electrocatalysts.Herein,we develop an isolated single-atom Ni catalyst regulated strategy to activate and stabilize the iron phthalocyanine molecule(Ni SA@FePc)toward a highly efficient CO_(2)RR process at low overpotential.The well-defined and homogenous catalytic centers with unique structures confer Ni SA@FePc with a significantly enhanced CO_(2)RR performance compared to single-atom Ni catalyst and FePc molecule and afford the atomic understanding on active sites and catalytic mechanism.As expected,Ni SA@FePc exhibits a high selectivity of more significant Faraday efficiency(≥95%)over a wide potential range,a high current density of~252 mA·cm^(−2) at low overpotential(390 mV),and excellent long-term stability for CO_(2)RR to CO.X-ray absorption spectroscopy measurement and theoretical calculation indicate the formation of NiN_(4)-O_(2)-FePc heterogeneous structure for Ni SA@FePc.And CO_(2)RR prefers to occur at the raised N centers of NiN4-O_(2)-FePc heterogeneous structure for Ni SA@FePc,which enables facilitated adsorption of*COOH and desorption of CO,and thus accelerated overall reaction kinetics.

Interfacial synthesis of crystalline quasi-two-dimensional polyaniline thin films for high-performance flexible on-chip micro-supercapacitors

Quasi-two-dimensional(q2 D)conducting polymer thin film synergizes the advantageous features of longrange molecular ordering and high intrinsic conductivity,which are promising for flexible thin film-based micro-supercapacitors(MSCs).Herein,we present the high-performance flexible MSCs based on highly ordered quasi-two-dimensional polyaniline(q2 D-PANI)thin film using surfactant monolayer assisted interfacial synthesis(SMAIS).Owing to high electrical conductivity,rich redox chemistry,and thin-film morphology,the q2 D-PANI MSCs show high volumetric specific capacitance(ca.360 F/cm^(3))and energy density(17.9 m Wh/cm^(3)),which outperform the state-of-art PANI thin-film based MSCs and promise for future flexible electronics.

On-surface synthesis and edge states of NBN-doped zigzag graphene nanoribbons

Zigzag graphene nanoribbons(ZGNRs)with spin-polarized edge states have potential applications in carbon-based spintronics.The electronic structure of ZGNRs can be effectively tuned by different widths or dopants,which requires delicately designed monomers.Here,we report the successful synthesis of ZGNR with a width of eight carbon zigzag lines and nitrogen-boronnitrogen(NBN)motifs decorated along the zigzag edges(NBN-8-ZGNR)on Au(111)surface,which starts from a specially designed U-shaped monomer with preinstalled NBN units at the zigzag edge.Chemical-bond-resolved non-contact atomic force microscopy(nc-AFM)imaging confirms the zigzag-terminated edges and the existence of NBN dopants.The electronic states distributed along the zigzag edges have been revealed after a silicon-layer intercalation at the interface of NBN-8-ZGNR and Au(111).Our work enriches the ZGNR family with a new dopant and larger width,which provides more candidates for future carbonbased nanoelectronic and spintronic applications.

Tuning the morphology of chevron-type graphene nanoribbons by choice of annealing temperature

Bottom-up synthesis of graphene nanoribbons (GNRs) by surface-assisted polymerization and cyclodehydrogenation of specifically designed precursor monomers has been shown to yield precise edges and doping.Here we use a precursor monomer containing sulfur atoms to fabricate nanostructures on a Au(111) surface at different annealing temperatures.The nanostructures have distinct configurations,varying from sulfur-doped polymers to sulfur-doped chevron-type GNRs (CGNRs) and,finally,pristine graphene nanoribbons with specific edges of periodic five-member carbon rings.Non-contact atomic force microscopy provides clear evidence for the cleavage of C-S bonds and formation of pristine CGNRs at elevated annealing temperatures.First-principles calculations show that the CGNRs exhibit negative differential resistance.

Sulfur-doped graphene nanoribbons with a sequence of distinct band gaps

不同于 graphene 表， graphene nanoribbons (GNR ) 能展出能被控制杂质做和 GNR 宽度和边结构调节的半导体的乐队差距特征。然而，完成如此的控制是在 GNR 的制造的主要挑战。V 形臂章类型 GNR 最近经由太古或代替 N 的 oligophenylene 单体的帮助表面的聚合被综合。原则上， GNR 异质接面能被混合二不同单体制作。在这份报纸，我们用代替硫的 oligophenylene 单体报导 V 形臂章类型 GNR 的制造和描述第一次生产 GNR 和相关 heterostructures。第一原则的计算证明 GNR 差距能被经由 debromination 和 intramolecular cyclodehydrogenation 从 cyclodehydrogenated 异构体使用不同的硫配置定制。这个特征应该由设计他们的硫配置为多重 GNR 异质接面的创造启用一条新途径。这些预言经由扫描通道显微镜学并且扫描通道光谱学被证实了。例如，我们发现了包含 S GNR 与不同乐队差距包含片断，即，导致量的一个序列的多重异质接面的一个序列点。这个不平常的 intraribbon 异质接面序列可能在使用量点的 nanoscale optoelectronic 应用是有用的。

An aqueous rechargeable zinc-ion battery on basis of an organic pigment

Neutral aqueous rechargeable zinc-ion batteries are receiving continuous attention because of their advantages of low cost,high safety,environmental friendliness,and high performance,which are difficult to attain with current organic electrolyte-based batteries.

Vinylene-Linked Two-Dimensional Covalent Organic Frameworks:Synthesis and Functions

Two-dimensional covalent organic frameworks(2D COFs)with covalently bonded repeat units and crystalline,porous framework backbones have attracted immense attention since the first 2D COFs were reported by Yaghi’s group in 2005.The extended single-layer structures of 2D COFs are also generally considered to be the 2D polymers.The precise incorporation of molecular building blocks into ordered frameworks enables the synthesis of novel organic materials with designable and predictable properties for specific applications,such as in optoelectronics,energy storage,and conversion.In particular,the 2Dπ-conjugated COFs(2D-c-COFs)represent a unique class of 2D conjugated polymers that have 2D molecular-periodic structures with extended in-planeπ-conjugations.In the 2D-c-COFs,the conjugated skeletons andπ−πstacking interactions can provide the pathways for electron transport,while the porous channel can enable the loading of active sites for catalysis and sensing.Thus far,the synthesis of 2D-c-COFs has been mostly limited to Schiff base chemistry based on the condensation reaction between amine and aldehyde/ketone monomers because the construction of 2D COFs as thermodynamically controlled products generally requires a highly reversible reaction for error-correction processes.However,the high reversibility of imine linkages would conversely endow moderateπ-electron delocalization due to the polarized carbon−nitrogen bonds and poor stability against strong acids/bases.To achieve robust and highly conjugated 2D-c-COFs,a series of synthesis strategies have been developed,including a one-step reversible reaction with a bond-forming−bond braking−bond reforming function,a quasi-reversible reaction combing reversible and irreversible processes,and postmodifications converting labile bonds to a robust linkage.Among all of the reported 2D-c-COFs,vinylene-linked(also sp^(2)-carbon-linked)2D covalent organic frameworks(V-2D-COFs)with high in-planeπ-conjugation have attracted increasing interest after we reported the first V-2D-COFs via a Knoevenagel polycondensation in 2016.Although CC bonds have low reversibility,making the synthesis of V-2D-COFs quite challenging,there have been around 40 V-2D-COFs reported over the past 5 years,which demonstrated the merits of V-2D-COFs combining with unique optoelectronic,redox,and magnetic properties.In this Account,we will summarize the development of V-2D-COFs,covering the important aspects of synthesis methods,design strategies,unique physical properties,and functions.First,the solvothermal synthesis of V-2D-COFs using different reaction methodologies and design principles will be presented,including Knoevenagel polycondensation,other aldol-type polycondensations,and Horner−Wadsworth−Emmons(HWE)polycondensation.Second,we will discuss the optoelectronic and magnetic properties of V-2D-COFs.Finally,the promising applications of V-2D-COF in the fields of sensing,photocatalysis,energy storage,and conversion will be demonstrated,which benefit from their robust vinylene-linked skeleton,full in-planeπ-conjugation,and tailorable structures.We anticipate that this Account will provide an intensive understanding of the synthesis of V-2D-COFs and inspire the further development of this emerging class of conjugated organic crystalline materials with unique physicochemical properties and applications across different areas.

Perspective towards atomic-resolution imaging of two-dimensional polymers

Recent years have witnessed the rise of an emerging class of synthetic twodimensional(2D)materials-2D polymers.The combination of organic chemistry and rational design of polymeric crystals has stimulated tremendous research efforts in the controlled synthesis of 2D polymers.However,despite the advancement in synthetic methodologies,the structural characterization of 2D polymers remains a significant challenge.Although aberration-corrected high-resolution transmission electron microscopy(AC-HRTEM)is capable of direct imaging of atomic structures with sub-Ångström resolution,electron radiation damage poses a substantial limit on the achievable image resolution due to instant decomposition of the molecular framework.In this Perspective,we will briefly discuss radiation damage mitigation strategies,which may eventually result in AC-HRTEM imaging of 2D polymers down to the atomic scale.

Ultrasensitive detection of Ebola matrix protein in a memristor mode

我们表明 Ebola VP40 矩阵蛋白质的直接 biosensing，用液体综合的 nanodevice 的一个 memristor 模式，基于塑造蜂房的硅 nanowires 的一个大数组。为了流更多，用 memristors 在 biodetection 的原则上点亮，我们设计了当前最小的电压差距 V 由包含第三个差距控制电极的差距 ( 门电压， V G ) 进系统。V G 是在传感器的活跃区域模仿需要的符号的控告的种类的存在。我们进一步与开始打开的控制差距显示出 biodetection 的优点(V 差距 0 ) ，它允许带任意的积极或否定的费用的 biomolecules 的最低集中的察觉；这个特征不是在以前的配置的现在。我们比较了 bio-memristor 表演，以它的察觉范围和敏感，到已经知道的地效果晶体管(联邦货物税) 的由操作一样的设备的模式。到我们的知识，这是用 nanoscaled 的 Ebola 矩阵蛋白质察觉的第一示范电的传感器。

富电子中心完全暴露镍团簇催化剂高性能电催化CO_(2)还原合成CO

单原子催化剂(SAC)因其最大化的金属原子利用率、独特的电子结构和优异的催化性能在电催化领域引起越来越多的关注.然而,对于需要同时活化不同反应物/中间体的反应来说,孤立的位点是不利的.完全暴露的金属簇催化剂(FECC),继承了SACs和金属纳米颗粒的优点,可以在其多原子位点上协同吸附和活化反应物/中间物,在电催化反应中显示了巨大的前景.文本开发了一种简便的方法从团簇到单原子尺度来调节Ni物种的原子分散度,以实现高效的二氧化碳还原.所制备的Ni FECC在CO合成中表现出了高达99%的法拉第效率,347.2 mA cm^(-2)的高CO分电流密度,以及在20 h电解下的优异稳定性.理论计算表明,多原子中心的构建和硫原子掺杂共同加速了反应动力学,从而提高了电化学CO_(2)还原合成CO的活性与选择性.

Selective and self-validating breath-level detection of hydrogen sulfide in humid air by gold nanoparticle-functionalized nanotube arrays

We demonstrate the selective detection of hydrogen sulfide at breath concentration levels under humid airflow,using a self-validating 64-channel sensor array based on semiconducting single-walled carbon nanotubes(sc-SWCNTs).The reproducible sensor fabrication process is based on a multiplexed and controlled dielectrophoretic deposition of sc-SWCNTs.The sensing area is functionalized with gold nanoparticles to address the detection at room temperature by exploiting the affinity between gold and sulfur atoms of the gas.Sensing devices functionalized with an optimized distribution of nanoparticles show a sensitivity of 0.122%/part per billion(ppb)and a calculated limit of detection(LOD)of 3 ppb.Beyond the self-validation,our sensors show increased stability and higher response levels compared to some commercially available electrochemical sensors.The cross-sensitivity to breath gases NH3 and NO is addressed demonstrating the high selectivity to H2S.Finally,mathematical models of sensors’electrical characteristics and sensing responses are developed to enhance the differentiation capabilities of the platform to be used in breath analysis applications.

Reversible hydrogenation restores defected graphene to graphene

Graphene as a two-dimensional material is prone to hydrocarbon contaminations,which can significantly alter its intrinsic electrical properties.Herein,we implement a facile hydrogenation-dehydrogenation strategy to remove hydrocarbon contaminations and preserve the excellent transport properties of monolayer graphene.Using electron microscopy we quantitatively characterized the improved cleanness of hydrogenated graphene compared to untreated samples.In situ spectroscopic investigations revealed that the hydrogenation treatment promoted the adsorption of water at the graphene surface,resulting in a protective layer against the re-deposition of hydrocarbon molecules.Additionally,the further dehydrogenation of hydrogenated graphene rendered a more pristine-like basal plane with improved carrier mobility compared to untreated pristine graphene.Our findings provide a practical post-growth cleaning protocol for graphene with maintained surface cleanness and lattice integrity to systematically carry a range of surface chemistry in the form of a well-performing and reproducible transistor.

Emerging reconfigurable electronic devices based on two-dimensional materials:A review

As the dimensions of the transistor,the key element of silicon technology,are approaching their physical limits,developing semiconductor technology with novel concepts and materials has been the main focus of scientific research and industry.In recent years,emerging reconfigurable technologies that offer device-level run-time reconfigurability have been explored and shown the potential to enhance device and circuit functions.Two-dimensional(2D)materials possess exquisite electronic properties and provide a suitable platform for reconfigurable technology owing to their atomic-thin thickness and high sensitivity to external electrical fields.In this review,we present an intensive survey of 2D-material-based devices with diverse reconfigurability,including carrier polarity,threshold voltage control,as well as multifunctional configurations enabled by 2D heterostructures.We discuss the working principles for these devices in detail and highlight the important figures of merit for performance improvement.We further provide a forward-looking perspective on the opportunities and challenges of these reconfigurable devices based on 2D materials in the field of computing technologies.