Reversible solid-liquid conversion enabled by self-capture effect for stable non-flow zinc-bromine batteries

Non-flow aqueous zinc-bromine batteries without auxiliary components(e.g.,pumps,pipes,storage tanks)and ion-selective membranes represent a cost-effective and promising technology for large-scale energy storage.Unfortunately,they generally suffer from serious diffusion and shuttle of polybromide(Br^(-),Br^(3-))due to the weak physical adsorption between soluble polybromide and host carbon materials,which results in low energy efficiency and poor cycling stability.Here,we develop a novel self-capture organic bromine material(1,10-bis[3-(trimethylammonio)propyl]-4,4'-bipyridinium bromine,NVBr4)to successfully realize reversible solid complexation of bromide components for stable non-flow zinc-bromine battery applications.The quaternary ammonium groups(NV^(4+)ions)can effectively capture the soluble polybromide species based on strong chemical interaction and realize reversible solid complexation confined within the porous electrodes,which transforms the conventional“liquid-liquid”conversion of soluble bromide components into“liquid-solid”model and effectively suppresses the shuttle effect.Thereby,the developed non-flow zinc-bromide battery provides an outstanding voltage platform at 1.7 V with a notable specific capacity of 325 mAh g^(-1)NVBr4(1 A g^(-1)),excellent rate capability(200 mAh g^(-1)NVBr4 at 20 A g^(-1)),outstanding energy density of 469.6 Wh kg^(-1)and super-stable cycle life(20,000 cycles with 100%Coulombic efficiency),which outperforms most of reported zinc-halogen batteries.Further mechanism analysis and DFT calculations demonstrate that the chemical interaction of quaternary ammonium groups and bromide species is the main reason for suppressing the shuttle effect.The developed strategy can be extended to other halogen batteries to obtain stable charge storage.

Recent progress in functionalized layered double hydroxides and their application in efficient electrocatalytic water oxidation

Layered double hydroxides (LDHs), a class of anionic clays consisting of brucite-like host layers and interlayer anions, have been widely investigated in the last decade due to their promising applications in many areas such as catalysis, ion separation and adsorption. Owing to the highly tunable compositi on and uniform distribution of metal cations in the brucite-like layers, as well as the facile exchangeability of intercalated anions, LDHs can be modified and functionalized to form various nanostructures/composites through versatile processes such as anion intercalation and exfoliation, decoration of nanoparticles, selfassembly with other two-dimensional (2D) materials, and controlled growth on conductive supports (e.g., nanowire arrays, nano tubes, 3D foams). In this article, we briefly review the recent advances on both the LDH nano structures and functionalized composites toward the applications in energy conversion, especially for water oxidation.

Rocking-chair ammonium ion battery with high rate and long-cycle life

Aqueous rechargeable ammonium-ion batteries(AIBs)have drew considerable attention because of their capacity for high rates,low cost,and high safety.However,developing desired electrodes requiring stable structure in the aqueous fast ammoniation/de-ammoniation becomes urgent.Herein,an ammonium ion full battery using Cu_(3)[Fe(CN)_(6)]_(2)(CuHCF)acting to be a cathode and barium vanadate(BVO)acting to be an anode is described.Its excellent electrochemical behavior of Prussian blue analogs and the perfectly matched lattice structure of NH_(4)^(+)is expected.And the open structure of vanadium compounds satisfies the fast ammoniation/de-ammoniation of NH4+is also achieved.As a result of these synergistic effects,the BVO//CuHCF full cell retains 80.5 percent of its capacity following 1000 cycling.These achievements provide new ideas for developing low-cost and long-life AIBs.

Highly robust zinc metal anode directed by organic–inorganic synergistic interfaces for wearable aqueous zinc battery

Flexible aqueous zinc batteries(FAZBs)with high safety and environmental friendliness are promising smart power sources for smart wearable electronics.However,the bare zinc anode usually suffers from damnable dendrite growth and rampant side reaction on the surface,greatly impeding practical applications in FAZBs.Herein,a composite polymer interface layer is artificially self‐assembled on the surface of the zinc anode by graft‐modified fluorinated monomer(polyacrylic acid‐2‐(Trifluoromethyl)propenoic acid,PAA‐TFPA),on which an organic–inorganic hybrid(PAA‐Zn/ZnF2)solid electrolyte interface(SEI)with excellent ionic conductivity is formed by interacting with Zn2+.Both the pouch cell and fiber zinc anode exhibit excellent plating/stripping reversibility after protecting by this organic–inorganic SEI,which can be stably cycled more than 3000 h in symmetric Zn||Zn cells or 550 h in fiber Zn||Zn cells.Additionally,this interface layer preserves zinc anode with excellent mechanical durability under various mechanical deformation(stably working for another 1200 h after bending 100 h).The corresponding PAA‐Zn/ZnF2@Zn||MnO2 full cell displays an ultra‐long life span(79%capacity retention after 3000 cycles)and mechanical robustness(85%of the initial capacity for another 3000 cycles after bending 100 times).More importantly,the as‐assembled cells can easily power smart wearable devices to monitor the user's health condition.

Amorphous nickel borate nanosheets as cathode material with high capacity and better cycling performance for zinc ion battery

Zinc-ion batteries are under current research focus because of their uniqueness in low cost and high safety.However,the pursuing of high-performance cathode materials of aqueous Zinc ion batteries(AZBs)with low cost,high energy density and long cycle life has become the key problem to be solved.Herein we synthesized a series of amorphous nickel borate(AM-NiBO)nanosheets by varying corrosion time with in-situ electrochemical corrosion method.The AM-NiBO-T13 as electrode material possesses a high areal capacity of 0.65 m Ah/cm^(2) with the capacity retention of 95.1%after 2000 cycles.In addition,the assembled AM-NiBO-T13//Zn provides high energy density(0.77 m Wh/cm^(2) at 1.76 m W/cm^(2)).The high areal capacity and better cycling performance can be owing to the amorphous nanosheets structure and the stable coordination characteristics of boron and oxygen in borate materials.It shows that amorphous nickel borate nanosheets have great prospects in the field of energy storage.

Design of cobalt-based catalysts with the uniformly distributed coreshell structure for ultra-efficient activation of peroxymonosulfate for tetracycline degradation

Catalysts that can rapidly degrade tetracycline(TC)in water without introducing secondary ion pollution have always been challenging.Herein,a cobalt-based catalyst(CoO_(x)@P-C)is prepared so that CoOx quantum particles(5e10 nm)are uniformly distributed on a linear substrate,and the outer layer is covered with a shell(P-C).The quantum particles of CoO_(x) provide many active sites for the reaction,which ensures the efficient degradation effect of the catalyst,and 30 mg/L TC can be completely degraded in only 5 min.The shell of the quantum particles'outer layer can effectively reduce ions'extravasation.The combination of the shell-like structure and the linear substrate greatly enhances the catalysis's stability and ensures that the catalyst is prepared into a film for practical application.The high catalytic activity of CoO_(x)@P-C is mainly due to the following factors:(1)Uniformly distributed ultra-small nanoparticles can provide many active sites.(2)The microenvironment formed by the core-shell structure enhances not only catalytic stability but also provides the driving force to improve the reaction rate.(3)The composite of CoO_(x) and P-C core-shell structure can accelerate electron transfer and generate many reactive oxygen species in a short time,which makes TC degrade extremely rapidly.

Recent advances in the improvement of g-C_(3)N_(4) based photocatalytic materials

g-C_(3)N_(4) have been widely used in the fields of photocatalytic hydrogen production,photocatalytic degradation of dyes and oxidative degradation of toxic gases due to their excellent performance.It has attracted extensive attention in recent years due to its highly efficient photocatalytic capacity of hydrogen generation,water oxidation,carbon dioxide reduction and degradation of organic pollutants.Because of the abundant carbon and nitrogen composition of the earth,large-scale production and industrial applications of this material are possible.The modification of this material makes its performance more excellent so that this new material can obtain a steady stream of vitality.These outstanding works have become important materials and milestones on the road to mankind's photocatalytic hydrogen production.This review will begin with the basic idea of designing,synthesizing and improving g-C_(3)N_(4) based photocatalytic materials,and introduce the latest development of g-C_(3)N_(4) photocatalysts in hydrogen production from four aspects of controlling the carbon/nitrogen ratio,morphology,element doping and heterojunction structure of g-C_(3)N_(4) materials.

Hierarchical Ni-Co-S@Ni-W-O core-shell nanosheet arrays on nickel foam for high-performance asymmetric supercapacitors

镍钴硫化物(Ni-Co-S ) 由于他们的优秀传导性和高电气化学的电容在电子设备为申请吸引了广泛的注意。为了便于 Ni-Co-S，优秀的率能力和这些的周期的稳定性的大规模实际申请，混合物必须充分被利用。因此，镍泡沫上的层次 Ni-Co-S@Ni-W-O (Ni-Co-S-W ) 核心 / 壳混血儿 nanosheet 数组经由一个灵巧的三步的热水的方法此处被设计并且综合，由在氩空气下面在一个管状的炉子退火列在后面。混合结构直接作为一个自立的电极被装配，它展出了 1,988 F

Hierarchical CuCo_2O_4@nickel-cobalt hydroxides core/shell nanoarchitectures for high-performance hybrid supercapacitors

Ni_(0.5)Co_(0.5)(OH)_2 nanosheets coated CuCo_2O_4 nanoneedles arrays were successfully designed and synthesized on carbon fabric. The core/shell nanoarchitectures directly served as the binder-free electrode with a superior capacity of 295.6 mAh g^(-1) at 1 Ag^(-1), which still maintained 220 mAh g^(-1) even at the high current density of 40 Ag^(-1), manifesting their enormous potential in hybrid supercapacitor devices. The asassembled CuCo_2O_4@Ni_(0.5)Co_(0.5)(OH)_2//AC hybrid supercapacitor device exhibited favorable properties with the specific capacitance as high as 90 Fg^(-1) at 1 Ag^(-1) and the high energy density of 32 Wh kg^(-1) at the power density of 800 Wkg^(-1). Furthermore, the as-assembled device also delivered excellent cycling performance(retaining 91.9% of the initial capacitance after 12,000 cycles at 8 Ag^(-1)) and robust mechanical stability and flexibility, implying the huge potential of present hierarchical electrodes in energy storage devices.

E-waste environmental contamination and harm to public health in China

The adverse effects of electronic waste （e-waste） on the human body have stirred up concern in recent years. China is one of the countries that confront serious pollution and human exposure of e-waste, and the majority of the population is exposed to potentially hazardous substances that are derived from informal e-waste recycling processes. This study reviews recent reports on human exposure to e-waste in China, with particular focus on exposure routes （e.g., inhalation and ingestion） and several toxicities of human （e.g., endocrine system, respiratory system, reproductive system, developmental toxicity, neurotoxicity, and genetic toxicity）. Pieces of evidence that associate e-waste exposure with human health effects in China are assessed. The role of toxic heavy metals （e.g., lead, cadmium, chromium, mercury, and nickel） and organic pollutants （e.g., polybrominated diphenyl ethers （PBDEs）, polychlorinated biphenyl （PCBs）, polycyclic aromatic hydrocarbons （PAHs）, polybrominated biphenyls （PBBs）, polyhalogenated aromatic hydrocarbons （PHAHs）, bisphenol A （BPA）） on human health is also briefly discussed.

Constructing highly dispersed 0D Co3S4 quantum dots/2D g-C3N4 nanosheets nanocomposites for excellent photocatalytic performance

The development of noble-metal-free catalysts with high efficiency photocatalytic properties is critical to the heterogeneous catalysis. Herein, zero-dimensional(0 D) metal sulfide quantum dots/two-dimensional(2 D) g-C3N4 nanosheets(Co3S4/CNNS) nanocomposites are synthesized by a two-step method, including the ways of in-situ deposition and water bath. The highly dispersed Co3S4 quantum dots(particle size is2–4 nm) are evenly and tightly fixed on CNNS, which can be used as co-catalyst to effectively replace noble metals to improve the photocatalytic properties of CNNS. Co3S4/CNNS-900 has the apparent quantum efficiency, which is up to 7.85% at 400 nm. At the same time, the H2 evolution rate of Co3S4/CNNS-900 is 20,536.4 lmol gà1 hà1, which is 555 times than CNNS. The excellent photocatalytic performance is due to the highly dispersed Co3S4 quantum dots on 2 D CNNS, which facilitate the formation of more active sites, Co3S4/CNNS promotes the separation and migration of photogenerated carriers, shortens the migration distance of photogenerated carriers, and eventually leads to an increase of the photocatalytic performance.

Synthesis of Z-scheme g-C3N4 nanosheets/Ag3PO4 photocatalysts with enhanced visible-light photocatalytic performance for the degradation of tetracycline and dye

Graphene-like C3N4/Ag3PO4 photocatalysts are synthesized by calcination and solutions precipitating method.The obtained g-C3N4/Ag3PO4 composites display excellent photocatalytic activity for the degradation of methylene orange(MO),rhodamine B(RhB)and tetracycline(TC)under visible light irradiation.The solutions containing RhB(10 mg/L)and MO(10 mg/L)can be efficiently degraded within15 min and 30 min.Especially,nearly 80%of TC(50 mg/L)is degraded within 20 min.which are much better than those of pure g-C3N4 nanosheets and Ag3PO4,implying that strong interaction and reasonable energy band alignment in the contact interface can effectively transfer the carries.Furthermore,the g-C3N4/Ag3PO4 composites exhibit the improved stability,and only a slight decrease is observed after three recycling runs.Moreover,the impact of inorganic ions and PH values on the degradation performance is rather small.The Z-scheme photocatalytic mechanism of the g-C3N4/Ag3PO4 composites based on the active species trapping experimental is proposed.This work demonstrates the promising applications of the g-C3N4/Ag3PO4 composites in environmental issues.

Enhanced photocatalytic activity of quantum-dot-sensitized one-dimensionally-ordered ZnO nanorod photocatalyst

An efficient photocatalyst was fabricated by assembling quantum dots （QDs） onto one-dimensionally-ordered ZnO nanorods, and the photocatalytic properties for Methyl Orange degradation were investigated by scanning electron microscopy, transmission electron microscopy, X-ray diffraction, UV-Vis-NIR absorption spectroscopy and photoluminescence. The results indicate that the catalyst with assembled QDs is more favorable for the degradation than the pristine ZnO nanorods. The QDs with core-shell structure lower the photocatalytic ability due to the higher carder transport barrier of the ZnS shell layer. Besides its degradation efficiency, the photocatalyst has several advantages given that the one-dimensionally-ordered ZnO nanorods have been grown directly on indium tin oxide substrates. The article provides a new method to design an effective and easily recyclable photocatalyst.

ZIF-67 derived hollow Ni-Co-Se nano-polyhedrons for flexible hybrid supercapacitors with remarkable electrochemical performances

Nano-polyhedral NiSe2/CoSe2(Ni-Co-Se) with hollow architectures are synthesized by selenizing the precursors of Ni-Co bimetallic hydroxides that are directly derived from ZIF-67.The as-fabricated Ni-Co-Se electrodes exhibit high specific capacitance of 1668 F/g at 1 A/g accompanying with outstanding rate capability(about 82.8% retention of the initial capacity at 20 A/g).The corresponding Ni-Co-Se//AC all-solid-state hybrid supercapacitors are assembled by directly using the Ni-Co-Se on carbon fabric as the positive electrode,which deliver high energy density and power density(38.5 Wh/kg at 802.1 W/kg,32.0 Wh/kg at 8008.8 W/kg),excellent cyclic stability(82.3% retention after 5000 cycle) and robust mechanical flexibility(no obvious attenuation at bending to different angles).This work will provide a new and smart route for constructing transition metal selenides for supercapacitor devices.

An integrated approach to configure rGO/VS_(4)/S composites with improved catalysis of polysulfides for advanced lithium-sulfur batteries

Lithium-sulfur(Li-S)battery is labeled as a promising high-energy-density battery system,but some inherent drawbacks of sulfur cathode materials using relatively complicated techniques impair the practical applications.Herein,an integrated approach is proposed to fabricate the high-performance rGO/VS_(4)/S cathode composites through a simple one-step solvothermal method,where nano sulfur and VS_(4) particles are uniformly distributed on the conductive rGO matrix.rGO and sulfiphilic VS_(4)provide electron transfer skeleton and physical/chemical anchor for soluble lithium polysulfides(LiPS).Meanwhile,VS_(4) could also act as an electrochemical mediator to efficiently enhance the utilization and reversible conversion of LiPS.Correspondingly,the rGO/VS_(4)/S composites maintain a high reversible capacity of 969 mAh/g at 0.2 C after 100 cycles,with a capacity retention rate of 82.3%.The capacity fade rate could lower to 0.0374%per cycle at 1 C.Moreover,capacity still sustains 795 m Ah/g after 100 cycles in the relatively high-sulfurloading battery(6.5 mg/cm^(2)).Thus,the suggested method in configuring the sulfur-based composites is demonstrated a simple and efficient strategy to construct the high-performance Li-S batteries.

Nickel/cobalt based materials for supercapacitors

The electrode materials as the key component of supercapacitors have attracted considerable research interests, especially for nickel/cobalt based materials by virtue of their superior electrochemical performance with multiple oxidation states for richer redox reactions, abundant natural resources, lower prices and toxicity. There are many advanced electrodes based on the nickel/cobalt materials exploited for the application of supercapacitors, however, some controversial statements have induced some confusion. Herein, we refine the mechanism of energy storage for the nickel/cobalt based materials for supercapacitors and reclassify them into battery-type materials with the corresponding devices named as hybrid supercapacitors.

Why the hydrothermal fluorinated method can improve photocatalytic activity of carbon nitride

Carbon nitride(CN) photocatalysts have attracted much attention due to their excellent photocatalytic properties.And hydrothermal fluorination is a common method to improve the photocatalytic effect of CN photocatalyst.Here,the influence of the band gap was first revealed of fluorination and hydroxylation of CN photocatalyst based on the first theoretical principle.Here,the effect of fluorination and hydroxylation on the CN band gap was discussed for the first time using the first theoretical principle.With F atoms and OH doping,the band gap of CN was significantly improved,conduction band and valence band moved up.Then,F-CN photocatalyst with F atoms and OH was successfully synthesized by a hydrothermal fluorinated method.Next,the reasons why F-CN photocatalyst was more effective than that of traditional CN photocatalyst were fully discussed.From the photocatalytic effect of photocatalyst(12,593.2 μmolg^(-1) h^(-1)to the morphology(super-small nanosheets),structure(homojunctions),composition(metal-free),specific surface area(54.1 m^(2)/g),visible light absorption response(AQE is10.9% at 420 nm) and photo-induced carrier life(14.13 ns).Therefore,this work has a great guiding effect on the development of CN photocatalyst.

Noble metal-free core-shell CdS/iron phthalocyanine Z-scheme photocatalyst for enhancing photocatalytic hydrogen evolution

Improving the separation efficiency of photogenerated carriers and broadening the light absorption range of the photocatalyst are two important factors for improving the performance of the photocatalyst.In this paper,a new and efficient Z-scheme Cd S/iron phthalocyanine(Cd S/Fe Pc)core-shell nanostructure composite material is prepared by a simple solid-phase reaction method.There are two key points in the preparation of composite materials:one is that hydrogen bonding energy is closely connected with Fe Pc,another is that Fe Pc can be uniformly assembled on Cd S nanoparticles.The photocatalytic hydrogen evolution(PHE)of the Cd S/Fe Pc nanocomposite(73.01μmol/h)is 2.6 times higher than that of pure Cd S(26.67μmol/h).In addition,after 4 photocatalytic cycles,the PHE of the Cd S/Fe Pc composite is still 92.3%of the first cycle.There are three reasons for this situation:(1)The Z-scheme heterojunction is formed to improve the separation efficiency of photogenerated carriers;(2)Fe Pc expands the visible light absorption range of Cd S;(3)The large core-shell contact area is favorable for the separation of photo-induced carriers at the interfaces.This research is conducive to the further development of new photocatalytic materials with high efficiency,low cost and simple preparation.

Defect engineering in Co-doped Ni_(3)S_(2) nanosheets as cathode for high-performance aqueous zinc ion battery

With the merits of low cost,environmental benignity,and high safety,aqueous zinc ion batteries(AZIBs)have great potential in the field of energy storage.In this paper,we craft a Co-doped Ni3 S2 with abundant sulfur vacancies as effective cathode materials(Co-Ni_(3) S_(2-x)) for AZIBs by hydrothermal and chemical reduction method.Notably,cobalt doping and abundant sulfur vacancies can effectively increase the conductivity and the number of active sites for electrochemical reactions,which gives the Co-Ni_(3) S_(2-x) electrode the outstanding capability to energy storage.By coupling Co-Ni_(3) S_(2-x) cathode with Zn anodes to assemble alkaline AZIBs,the Co-Ni_(3) S_(2-x)//Zn full battery exhibits excellent specific capacity(183.9 mAh g^(-1) at 1 A g^(-1),based on cathode mass) and extraordinary cycling durability(72.9% capacity retention after 6000 cycles).First-principles calculations based on density functional theory(DFT) confirm that the Co-Ni_(3) S_(2-x) electrode has strong energy storage capacity and electrochemical stability.The results provide an extremely significant reference in designs of self-supported bimetallic sulfide nanosheets,which have promising applications in high-performance energy storage devices.

Rational construction of phosphate layer to optimize Cu-regulated Fe_(3)O_(4) as anode material with promoted energy storage performance for rechargeable Ni-Fe batteries

Flexible aqueous energy storage devices with high security and flexibility are crucial for the progress of wearable energy storage.Particularly,aqueous rechargeable Ni-Fe batteries owning a large theoretical capacity,low cost and outstanding safety characteristics have emerged as a promising candidate for flexible aqueous energy storage devices.Herein,Cu-doped Fe_(3)O_(4)(CFO)with 3D coral structure was prepared by doping Cu^(2+) based on Fe_(3)O_(4)nanosheets(FO).Furthermore,the Fe-based anode material(CFPO)grown on carbon fibers was obtained by reconstructing the surface of CFO to form a low-crystallization shell which can enhance the ion transport.Excitingly,the newly developed CFPO electrode as an innovative anode material further exhibited a high capacity of 117.5 mAh g^(-1)(or 423 F g^(-1))at 1 A g^(-1).Then,the assembled aqueous Ni-Fe batteries with a high cell-voltage output of 1.6 V deliver a high capacity of 49.02 mAh g^(-1) at 1 A g^(-1) and retention ratio of 96.8%for capacitance after 10000 continuous cycles.What’s more,the aqueous quasi-solid-state batteries present a remarkable maximal energy density of 45.6 Wh kg^(-1) and a power density of 12 kW kg^(-1).This work provides an innovative and feasible way and optimization idea for the design of high-performance Fe-based anodes,and may promote the development of a new generation of flexible aqueous Ni-Fe batteries.