The application of nanostructured transition metal sulfides as anodes for lithium ion batteries

With wide application of electric vehicles and large-scale in energy storage systems, the requirement ofsecondary batteries with higher power density and better safety gets urgent. Owing to the merits of hightheoretical capacity, relatively low cost and suitable discharge voltage, much attention has been paid tothe transition metal sulfides. Recently, a large amount of research papers have reported about the appli-cation of transition metal sulfides in lithium ion batteries. However, the practical application of transitionmetal sulfides is still impeded by their fast capacity fading and poor rate performance. More well-focusedresearches should be operated towards the commercialization of transition metal sulfides in lithium ionbatteries. In this review, recent development of using transition metal sulfides such as copper sulfides,molybdenum sulfides, cobalt sulfides, and iron sulfides as electrode materials for lithium ion batteriesis presented. In addition, the electrochemical reaction mechanisms and synthetic strategy of transitionmetal sulfides are briefly summarized. The critical issues, challenges, and perspectives providing a fur-ther understanding of the associated electrochemical processes are also discussed.

Manipulating d-d orbital hybridization induced by Mo-doped Co_(9)S_(8) nanorod arrays for high-efficiency water electrolysis

Precisely refining the electronic structure of electrocatalysts represents a powerful approach to further optimize the electrocatalytic performance.Herein,we demonstrate an ingenious d-d orbital hybridization concept to construct Mo-doped Co_(9)S_(8) nanorod arrays aligned on carbon cloth(CC)substrate(abbreviated as Mo-Co_(9)S_(8)@CC hereafter)as a high-efficiency bifunctional electrocatalyst toward water electrolysis.It has experimentally and theoretically validated that the 4d-3d orbital coupling between Mo dopant and Co site can effectively optimize the H_(2)O activation energy and lower H^(*)adsorption energy barrier,thereby leading to enhanced hydrogen evolution reaction(HER)and oxygen evolution reaction(OER)activities.Thanks to the unique electronic and geometrical advantages,the optimized Mo-Co_(9)S_(8)@CC with appropriate Mo content exhibits outstanding bifunctional performance in alkaline solution,with the overpotentials of 75 and 234 mV for the delivery of a current density of 10 mA cm^(-2),small Tafel slopes of 53.8 and 39.9 mV dec~(-1)and long-term stabilities for at least 32 and 30 h for HER and OER,respectively.More impressively,a water splitting electrolylzer assembled by the self-supported Mo-Co_(9)S_(8)@CC electrode requires a low cell voltage of 1.53 V at 10 mA cm^(-2)and shows excellent stability and splendid reversibility,demonstrating a huge potential for affordable and scalable electrochemical H_(2) production.The innovational orbital hybridization strategy for electronic regulation herein provides an inspirable avenue for developing progressive electrocatalysts toward new energy systems.

Applications of Rare Earth Promoted Transition Metal Sulfides in Electrocatalysis

With the rapid consumption of fossil fuels and the resulting environmental problems,researchers are working to find sustainable alternative energy and energy storage and conversion methods.Transition metal sulfur compounds have attracted extensive attention due to their excellent electrical conductivity,low cost,adjustable components and good electrocatalytic performance.As an alternative to noble metal catalysts,they have emerged as a promising electrocatalyst.However,their low catalytic activity and poor stability limit their large-scale practical applications.Rare earth elements,known as industrial vitamins,are widely used in various fields due to their special redox properties,oxygen affinity and electronic structure.Therefore,the construction of rare earth promoted transition metal sulfides is of far-reaching significance for the development of catalysts.Here,we review the applications of various rare earth promoted transition metal sulfides in energy storage and conversion in recent years,which focuses on three ways in rare earth promoted transition metal sulfide,including doping,interfacial modification engineering and structural facilitation.As well,these materials are used in electrochemical reactions such as OER,HER,ORR,CO_(2)RR,and so on,in order to explore the important role of rare earth in the field of electrocatalysis,the future challenges and opportunities.

Supercapacitive properties of MnNiS_(x)@Ti_(3)C_(2)T_(x) MXene positive electrode assisted by functionalized ionic liquid

MnNiS_(x)@Ti_(3)C_(2)T_(x)as the positive electrode of supercapacitor was successfully prepared by hydrothermal method with the assistance of amino-functionalized ionic liquids.The micromorphological structures of MnNiS_(x)@Ti_(3)C_(2)T_(x)were analyzed using X-ray diffraction,scanning electron microscope,X-ray photoelectron spectroscopy,transmission electron microscope,and energy dispersive spectrometer to reveal the synergistic effect between MnNiSxand Ti_(3)C_(2)T_(x)MXene.MnNiS——x grew into a three-dimensional coral-like structure on the surface and between layers of Ti_(3)C_(2)T_(x)nanosheets.This structure alleviated the collapse and stacking of Ti_(3)C_(2)T_(x),increased the specific surface area of Ti_(3)C_(2)T_(x),and promoted the charges transfer on the surface of Ti_(3)C_(2)T_(x).The electrochemical performances of MnNiS_(x)@Ti_(3)C_(2)T_(x)positive electrode,such as cyclic voltammetry,galvanostatic charge/discharge,and electrochemical impedance spectroscopy,were investigated.The synergistic effect between MnNiSxand Ti_(3)C_(2)T_(x)MXene improved the specific capacitance and the capacitance retention of the MnNiS_(x)@Ti_(3)C_(2)T_(x)electrode.An asymmetric solid-state supercapacitor(ASC)assembled using MnNiS_(x)@Ti_(3)C_(2)T_(x)as cathode material had the power density of 816.34 W·kg^(-1),and the energy density of 35.11 Wh·kg^(-1).The capacitance retention of ASC reached 98% after 5000 cycles at a current density of 5 A·g^(-1).

Shining light on transition metal sulfides:New choices as highly efficient antibacterial agents

Globally,millions of people die of microbial infection-related diseases every year.The more terrible situation is that due to the overuse of antibiotics,especially in developing countries,people are struggling to fight with the bacteria variation.The emergence of super-bacteria will be an intractable environmental and health hazard in the future unless novel bactericidal weapons are mounted.Consequently,it is critical to develop viable antibacterial approaches to sustain the prosperous development of human society.Recent researches indicate that transition metal sulfides(TMSs)represent prominent bactericidal application potential owing to the meritorious antibacterial performance,acceptable biocompatibility,high solar energy utilization efficiency,and excellent photo-to-thermal conversion characteristics,and thus,a comprehensive review on the recent advances in this area would be beneficial for the future development.In this review article,we start with the antibacterial mechanisms of TMSs to provide a preliminary understanding.Thereafter,the state-of-the-art research progresses on the strategies for TMSs materials engineering so as to promote their antibacterial properties are systematically surveyed and summarized,followed by a summary of the practical application scenarios of TMSs-based antibacterial platforms.Finally,based on the thorough survey and analysis,we emphasize the challenges and future development trends in this area.

Progress and Prospects of Transition Metal Sulfides for Sodium Storage

Sodium-ion battery(SIB),one of most promising battery technologies,offers an alternative low-cost solution for scalable energy storage.Developing advanced electrode materials with superior electrochemical performance is of great significance for SIBs.Transition metal sulfides that emerge as promising anode materials have advantageous features particularly for electrochemical redox reaction,including high theoretical capacity,good cycling stability,easily-controlled structure and modifiable chemical composition.In this review,recent progress of transition metal sulfides based materials for SIBs is summarized by discussing the materials properties,advanced design strategies,electrochemical reaction mechanism and their applications in sodium-ion full batteries.Moreover,we propose several promising strategies to overcome the challenges of transition metal sulfides for SIBs,paving the way to explore and construct advanced electrode materials for SIBs and other energy storage devices.

Applications of transition-metal sulfides in the cathodes of lithium-sulfur batteries

Lithium-sulfur(Li-S)batteries are considered as one of the most promising candidates for next-generation energy storage systems with high energy density and reliable performance.However,the commercial applications of lithium-sulfur batteries is hindered by several shortcomings like the poor conductivity of sulfur and its reaction products,and the loss of active materials owing to the diffusion of lithium polysulfides(LiPSs)into the electrolyte.Hence,the effective restraining of the LiPSs and the promotion of the sluggish conversion are highly demanded to fulfill the potential of lithium-sulfur batteries.Here,we summarize the applications of transition-metal sulfides(TMSs)in the cathodes over recent years and demonstrate the unique advantages they possess to realize reliable long-life lithium-sulfur batteries.

Multi-Dimensional Composite Frame as Bifunctional Catalytic Medium for Ultra-Fast Charging Lithium-Sulfur Battery

The shuttle effect of soluble lithium polysulfides(LiPSs)between electrodes and slow reaction kinetics lead to extreme inefficiency and poor high current cycling stability,which limits the commercial application of Li-S batteries.Herein,the multi-dimensional composite frame has been proposed as the modified separator(MCCoS/PP)of Li-S battery,which is composed of CoS_(2) nanoparticles on alkali-treated MXene nanosheets and carbon nanotubes.Both experiments and theoretical calculations show that bifunctional catalytic activity can be achieved on the MCCoS/PP separator.It can not only promote the liquid-solid conversion in the reduction process,but also accelerate the decomposition of insoluble Li_(2)S in the oxidation process.In addition,LiPSs shuttle effect has been inhibited without a decrease in lithium-ion transference numbers.Simultaneously,the MCCoS/PP separator with good LiPSs adsorption capability arouses redistribution and fixing of active substances,which is also beneficial to the rate performance and cycling stability.The Li-S batteries with the MCCoS/PP separator have a specific capacity of 368.6 mAh g^(−1) at 20C,and the capacity decay per cycle is only 0.033%in 1000 cycles at 7C.Also,high area capacity(6.34 mAh cm^(−2))with a high sulfur loading(7.7 mg cm^(−2))and a low electrolyte/sulfur ratio(7.5μL mg^(−1))is achieved.

Theoretical Study on the Dehydrogenation Reaction of H_2S by VS^+ (~3Σ^-)

The dehydrogenation reaction of H2S by the ^3Σ^- ground state of VS^＋： VS^＋ ＋ H2S → VS2^＋ ＋ H2 has been studied by using Density Functional Theory （DPT） at the B3LYP/DZVP level. It is found that the reaction proceeds along two possible pathways （A and B） yielding two isomer dehydrogenation products VS2^＋-1 （^3B2） and VS2^＋-2 （^3A1）, respectively. For both pathways, the reaction has a two-step-reaction mechanism that involves the migration of two hydrogen atoms from S2 to V^＋, respectively. The migration of the second hydrogen via TS3 and that of the first via TS4 are the rate-determining steps for pathways A and B, respectively. The activation energy is 17.4 kcal/mol for pathway A and 22.8 kcal/mol for pathway B relative to the reactants. The calculated reaction heat of 9.9 kcal/mol indicates the endothermicity of pathway A and that of -11.9 kcal/mol suggests the exothermicity of pathway B.

Strain engineering of electronic and magnetic properties of Ga_2S_2 nanoribbons

Using first-principles calculations, we study the tailoring of the electronic and magnetic properties of gallium sulfide nanoribbons（Ga2S2NRs） by mechanical strain. Hydrogen-passivated armchair-and zigzag-edged NRs（ANRs and ZNRs）with different widths are investigated. Significant effects in band gap and magnetic properties are found and analyzed. First,the band gaps and their nature of ANRs can be largely tailored by a strain. The band gaps can be markedly reduced, and show an indirect-direct（I-D） transition under a tensile strain. While under an increasing compressive strain, they undergo a series transitions of I-D-I-D. Five strain zones with distinct band structures and their boundaries are identified. In addition,the carrier effective masses of ANRs are also tunable by the strain, showing jumps at the boundaries. Second, the magnetic moments of（ferromagnetic） ZNRs show jumps under an increasing compressive strain due to spin density redistribution,but are unresponsive to tensile strains. The rich tunable properties by stain suggest potential applications of Ga2S2 NRs in nanoelectronics and optoelectronics.

泡沫镍上生长的具有三明治纳米结构的MnCo_(2)O_(4)@NiCoMnS_(4)用于高性能水系非对称超级电容器

本文介绍了一种由水热生长的MnCo_(2)O_(4)(MCO)纳米线以及随后电沉积的NiCoMnS_(4)(NCMS)纳米片组成的高性能超级电容器电极材料,即泡沫镍上生长的MCO@NCMS.由于其多孔和互联的纳米结构以及MCO和NCMS的协同效应,在1 mA cm^(-2)处实现了12,020.8 mF cm^(-2)的高电容,并展现出良好的倍率性能以及循环稳定性.电化学测试表明,组装成的水性非对称超级电容器在0.800 mW cm^(-2)的功率密度下,达到0.611 mW h cm^(-2)的高能量密度并具有良好的循环稳定性,即在15,000次充放电循环后,容量保持率可达90%,且保持100%的库仑效率.

A review of transition metal chalcogenide/graphene nanocomposites for energy storage and conversion

To meet the ever-increasing energy demands, advanced electrode materials are strongly requested for the exploration of advanced energy storage and conversion technologies, such as Li-ion batteries, Li-S batteries, Li-]Zn-air batteries, supercapacitors, dye-sensitized solar cells, and other electrocatalysis process （e.g., oxygen reductionlevolution reaction, hydrogen evolution reaction）. Transition metal chalcogenides （TMCs, Le., sulfides and selenides） are forcefully considered as an emerging candidate, owing to their unique physical and chemical properties. Moreover, the integration of TMCs with conductive graphene host has enabled the significant improvement of electrochemical performance of devices. In this review, the recent research progress on TMC]graphene composites for applications in energy storage and conversion devices is summarized. The preparation process of TMC]graphene nanocomposites is also included. In order to promote an in-depth understanding of performance improvement for TMC/graphene materials, the operating principle of various devices and technologies are briefly presented. Finally, the perspectives are given on the design and construction of advanced electrode materials.

Coupling interface constructions of FeOOH/NiCo_(2)S_(4)by microwave-assisted method for efficient oxygen evolution reaction

The oxygen evolution reaction(OER) with slow kinetics is the rate-limiting step of electrochemical water splitting.A reasonable construction of interface nanostructures is the key to improving the OER efficiency and durability of non-noble metal electrocatalysts.In this study,a FeOOH/NiCo_(2)S_(4) core-shell nanorod array with abundant heterogeneous interfaces and high density of active sites was successfully prepared by a microwave-as sis ted method.Experimental research and theoretical calculations show that the abundant strong coupling Ni/Co-S-Fe interface helps in adjusting the electronic structure of the material surface,optimizing the adsorption energy of the intermediate,and realizing an efficient catalytic process.The as-synthesized FeOOH/NiCo_(2)S_(4)/NF composite electrode exhibited lower overpotential(198 mV) and Tafel slope(62 mV·dec^(-1)) at a current density of 10 mA·cm^(-2)and excellent stability(approximately 100% retention after100 h) than the NiCo_(2)S_(4)/nickel foam(NF).In conclusion,constructing heterojunctions with complementary active materials is an effective strategy to design efficient and robust OER electrocatalysts.

Sulfur-deficient CoNi_(2)S_(4)nanoparticles-anchored porous carbon nanofibers as bifunctional electrocatalyst for overall water splitting

Water electrolysis technology is considered to be one of the most promising means to produce hydrogen.Herein,aiming at the problems of high overpotential and slow kinetics in water splitting,N-doped porous carbon nanofibers-coupled CoNi_(2)S_(4)nanoparticles are prepared as bifunctional electrocatalyst.In the strategy,NaCl is used as the template to prepare porous carbon nanofibers with a large surface area,and sulfur vacancies are created to modulate the electronic structure of CoNi_(2)S_(4).Electron spin resonance confirms the formation of abundant sulfur vacancies,which largely reduce the bandgap of CoNi_(2)S_(4)from 1.68 to 0.52 eV.The narrowed bandgap is conducive to the migration of valence electrons and decreases the charge transfer resistance for electrocatalytic reaction.Moreover,the uniform distribution of CoNi_(2)S_(4)nanoparticles on carbon nanofibers can prevent the aggregation and facilitate the exposure of electrochemical active sites.Therefore,the composite catalyst exhibits low overpotentials of 340 mV@100 mA·cm^(-2)for oxygen evolution reaction and 380 mV@100 mA·cm^(-2)for hydrogen evolution reaction.The assembled electrolyzer requires 1.64 V to achieve 10 mA·cm^(-2)for overall water-splitting with good long-term stability.The excellent performance results from the synergistic effect of porous structures,sulfur deficiency,nitrogen doping,and the well-dispersed active component.

Rational design and synthesis of nanosheets self-assembled hierarchical flower-ball-like CuFeS_(2)for boosted wide temperature sodium-ion batteries

Nano-structure designs with conductive networks have been demonstrated as an efficient strategy to boost sodium storage properties for transition metal sulfides.Herein,an exquisite nanosheets self-assembled hierarchical flower-ball-like CuFeS_(2)embedded into the reduced graphene oxide(RGO)nanosheet matrix(F-CuFeS_(2)@RGO)is fabricated via a concise two-step solvothermal method.Such a well-designed architecture affords increased active reaction interfaces and enhanced mixed ionic/electronic conductivity.Meanwhile,the external RGO matrix can effectively alleviate the volume expansion and create a stable structure during long cycles.As a result,the composite material exhibits a high reversible capacity of 559 mAh·g^(-1)at 0.1 A·g^(-1),a superior rate capability of 455 mAh·g^(-1)at 5 A·g^(-1)and excellent cyclic stability with 96%capacity retention after 4800 cycles at 5 A·g^(-1),among the best in the state-of-the-art transition metal sulfide anodes.Especially,F-CuFeS_(2)@RGO delivers outstanding low-temperature performances with a high capacity retention of 100%and 91%at-20 and-40℃,respectively,over 200 cycles.The proposed hierarchical structure fabrication paves a new direction in the design of high-performance electrodes for all-temperature energy storage applications.

In-situ constructed three-dimensional MoS_(2)–MoN heterostructure as the cathode of lithium–sulfur battery

Lithium-sulfur batteries are recognized as one of the most promising next-generation high-performance energy storage systems. However, obstacles like the irreversible capacity loss hinder its broad application. Herein,we fabricated an interconnected three-dimensional MoS_(2)-MoN heterostructure(3D-MoS_(2)-MoN) via a facile salttemplate method, overcoming the intrinsic shortcomings such as poor conductivity and compact morphology of traditionally-synthesized transition metal sulfides(TMSs).Furthermore, excellent electrocatalysis ability and hierarchical pore structure effectively accelerate the sluggish lithium polysulfides conversions during cycling. As a result, 3D-MoS_(2)-MoN showed a high initial specific capacity of 1466 mAh·g^(-1)and excellent high-rate capability up to 4℃. A stable cycling performance with a sulfur loading of 2 mg·cm^(-2) was realized with a low decay rate of 0.069% per cycle. This work introduced a rational design route for the appliance of TMSs in the lithiumsulfur batteries.

Highly efficient and magnetically separable nano-CuFe_2O_4 catalyzed S-arylation of thiourea by aryl/heteroaryl halides

The non-toxic and magnetically separable nano-CuFeOcatalyzed synthesis of symmetrical aryl sulfides by the reaction of thiourea with a wide variety of aryl halides,including aryl chlorides has been reported.Excellent yields of products have been obtained under ligand-free conditions and without the use of any expensive catalyst,such as palladium.

A universal cooperative assembly-oriented strategy for VS_(4) nanorod decoration on carbon nanostructures with enhanced magnesium storage properties

VS_(4) has a unique layered atomic chain structure and has the potential to become a high-performance cathode material of magnesium-ion batteries with a high capacity and long cycle life.However,low conductivity and sluggish Mg^(2+)diffusivity during cycling limit its practical application in large-scale energy storage.Herein,a cooperative assembly-directed strategy is adopted to synthesize VS_(4) nanorods grown in situ on carbon nanotubes(CNTs/VS_(4)).VS_(4) nanorods are tightly anchored to CNTs through V-O-C interface covalent bonds,and CNTs can enhance the electronic conductivity of the nanocomposite.In addition,the ion insertion reaction using Mg^(2+)and Mg Cl^(+)as carriers reduces the polar barrier for divalent Mg^(2+)ion transport.This rationally designed architecture promotes ion diffusion and electron transfer,thus facilitating reaction kinetics.The cooperative assembly-oriented strategy can endow CNTs/VS_(4) with excellent magnesium storage properties,including a high reversible capacity of 223.2 m Ah g^(-1)at a current density of 50 m A g^(-1),a remarkable discharge capacity of 91.8 m Ah g^(-1)even at 2,000 m A g^(-1),and an impressive capacity retention of 85.2% after 1,000 cycles at 500 m A g^(-1).Moreover,this strategy can serve as a general synthetic method for the complexation of VS_(4) with other carbon nanostructures.