N-Doping-Induced Amorphization for Achieving Ultrastable Aqueous Zinc-Ion Batteries.

Vanadium-based oxides, known for their high capacity and low cost, have garnered significant attention as promising cathode candidates in aqueous zinc-ion batteries. Nonetheless, their poor rate performance and limited durability in aqueous electrolytes present a challenge to the realistic implementation of vanadium-based aqueous zinc-ion batteries. Here, we synthesized nitrogen-doped V2O3@C (N-V2O3@N-C) via ammonia treatment of V2O3@C derived from vanadium-based metal-organic framework (V-MOF), aiming to achieve outstanding rate and cycling performance. The N-V2O3@N-C electrode exhibits notable in situ self-transformation into an amorphous state. Density functional theory calculations reveal that the distorted N-V2O3 structure and uneven charge distribution result in the creation of an amorphous state. As expected, Zn/N-V2O3@N-C aqueous zinc-ion batteries can achieve remarkable specific capacity (349.0 mAh g-1 at 0.1 A g-1), along with impressive rate performance, showcasing a capacity of 253.5 mAh g-1 at 5 A g-1 and exceptional durability at 5 A g-1 (96.4% after 1350 cycles). The employed induced amorphization approach offers novel perspectives for designing high-performance cathodes that exhibit both sturdy structures and extended cycling lifespans.

Two-dimensional/three-dimensional hierarchical self-supporting potassium ammonium vanadate@MXene hybrid film for superior performance aqueous zinc ion batteries.

Currently, aqueous zinc ion batteries (AZIBs) have grown to be a good choice for large-scale energy storage systems due to their high theoretical specific capacity, low redox potential, low cost, and non-toxicity of the aqueous electrolyte. However, it is still challenging to obtain high specific capacity and stability suitable cathodes. Herein, hierarchical self-supporting potassium ammonium vanadate@MXene (KNVO@MXene) hybrid films were prepared by vacuum filtration method. Due to the three-dimensional nanoflower structure of KNVO with dual ions intercalation, high conductivity of two-dimensional Ti3C2Tx MXene, and the hierarchical self-supporting structure, the AZIB based on the KNVO@MXene hybrid film cathode possessed superior specific capacity (481 mAh/g at 0.3 A/g) and cycling stability (retaining 125 mAh/g after 1000 cycles at a high current density of 10 A/g). In addition, the storage mechanism was revealed by various ex-situ characterizations. Hence, a new viewpoint for the preparation of AZIB self-supporting cathode materials is presented.

Facile synthesis of pyrite FeS2 on carbon spheres for high-efficiency Fenton-like reaction.

Designing iron-based catalysts for Fenton-like reactions with peroxymonosulfate (PMS) as oxidants have attracted growing attentions. Herein, pyrite FeS2 supported on carbon spheres (FeS2@C) is synthesized by a facile low-temperature method. The FeS2@C/PMS system can degrade carbamazepine (CBZ) effectively in a wide pH range. Sulfate radicals (SO4·-), hydroxyl radicals (·OH), superoxide radical (O2·-), and singlet oxygen (1O2) are the responsible reactive oxygen species (ROSs) for CBZ degradation. Moreover, in the simulated fixed-bed reactor, the FeS2@C/PMS system can maintain a high CBZ removal ratio of >95% for than 8 h, exhibiting its excellent stability. The outstanding performance of FeS2@C/PMS system is attributed to the presence of carbon spheres and lattice S2-, which together promote the Fe(III)/Fe(II) redox cycle. The FeS2@C is a promising catalyst due to its facile synthesis, low cost, high efficiency, and excellent stability to activate PMS for organics degradation.

Sulfate radical dominated rapid pollutants degradation leaded by selenium vacancies in core-shell N-doped carbon wrapped cobalt diselenide nanospheres.

Herein, a new heterogeneous CoSe2-x@NC material with abundant selenium vacancies is synthesized via an in-situ carbonization-selenization process from cobaltic metal organic framework (Co-MOF). The obtained CoSe2-x@NC has a unique electronic structure and rich active sites, which can activate peroxymonosulfate (PMS) to degrade carbamazepine (CBZ) with superior catalytic performance and stability. The quenchingexperiments and EPR test show that SO4•- is the dominant reactive oxidation species (ROSs) for CBZ degradation. Significantly, systemic electrochemical tests and theoretical calculations illustrated that the dominant role of SO4•- is attributed to the existence of abundant selenium vacancies in CoSe2-x@NC, which can adjust the density of electron cloud of the Co atoms in CoSe2-x@NC to improve the PMS adsorption and promoting the conversion of transition metallic redox pairs (Co3+/Co2+). This work provides a facile way to improve the activity and stability of CoSe2 by defect engineering in the PMS based advanced oxidation process (AOPs).

Enabling Uniform and Stable Lithium-Ion Diffusion at the Ultrathin Artificial Solid-Electrolyte Interface in Siloxene Anodes.

Constructing a stable and robust solid electrolyte interphase (SEI) has a decisive influence on the charge/discharge kinetics of lithium-ion batteries (LIBs), especially for silicon-based anodes which generate repeated destruction and regeneration of unstable SEI films. Herein, a facile way is proposed to fabricate an artificial SEI layer composed of lithiophilic chitosan on the surface of two-dimensional siloxene, which has aroused wide attention as an advanced anode for LIBs due to its special characteristics. The optimized chitosan-modified siloxene anode exhibits an excellent reversible cyclic stability of about 672.6 mAh g-1 at a current density of 1000 mA g-1 after 200 cycles and 139.9 mAh g-1 at 6000 mA g-1 for 1200 cycles. Further investigation shows that a stable and LiF-rich SEI film is formed and can effectively adhere to the surface during cycling, redistribute lithium-ion flux, and enable a relatively homogenous lithium-ion diffusion. This work provides constructive guidance for interface engineering strategy of nano-structured silicon anodes.

Advances in Aqueous Zinc Ion Batteries based on Conversion Mechanism: Challenges, Strategies, and Prospects.

Recently, aqueous zinc-ion batteries with conversion mechanisms have received wide attention in energy storage systems on account of excellent specific capacity, high power density, and energy density. Unfortunately, some characteristics of cathode material, zinc anode, and electrolyte still limit the development of aqueous zinc-ion batteries possessing conversion mechanism. Consequently, this paper provides a detailed summary of the development for numerous aqueous zinc-based batteries: zinc-sulfur (Zn-S) batteries, zinc-selenium (Zn-Se) batteries, zinc-tellurium (Zn-Te) batteries, zinc-iodine (Zn-I2 ) batteries, and zinc-bromine (Zn-Br2 ) batteries. Meanwhile, the reaction conversion mechanism of zinc-based batteries with conversion mechanism and the research progress in the investigation of composite cathode, zinc anode materials, and selection of electrolytes are systematically introduced. Finally, this review comprehensively describes the prospects and outlook of aqueous zinc-ion batteries with conversion mechanism, aiming to promote the rapid development of aqueous zinc-based batteries.

N-Terminalized Ti3 C2 Tx MXene for Supercapacitor with Extraordinary Pseudocapacitance Performance.

MXenes have demonstrated significant potential in electrochemical energy storage, particularly in supercapacitors, owing to their exceptional properties. The surface terminal groups of MXene play a pivotal role in pseudocapacitive mechanism. Considering the hindered electrolyte ion transport caused by -F terminal groups and the limited ion binding sites associated with -O terminal groups, this study proposes a novel strategy of replacing -F with -N terminal groups. The modulated MXene-N electrode, featuring a substantial number of -N terminal groups, demonstrates an exceptionally high gravimetric capacitance of 566 F g-1 (at a scan rate of 2 mV s-1 ) or 588 F g-1 (at a discharge rate of 1 A g-1 ) in 1 м H2 SO4 electrolyte, and the potential window is significantly increased. Furthermore, subsequent spectra analysis and density functional theory calculations are employed to investigate the mechanism associated with -N terminal groups. This work exemplifies the significance of terminal modulation in the context of electrochemical energy storage.

Interfacial assembled porous bismuthene/Ti3C2Tx MXene heterostructure for highly efficient capacitive deionization.

Capacitive deionization (CDI) is perceived as a promising technology for freshwater production owing to its environmentally friendly nature and low energy consumption. To date, the development of high-performance electrode materials represents the foremost challenge for CDI technology. In this work, the porous bismuthene/MXene (P-Bi-ene/MXene) heterostructure was synthesized using a simple interfacial self-assembly method with two-dimensional (2D) bismuthene and Ti3C2Tx MXene. Within the P-Bi-ene/MXene heterostructure, the porous structure can increase the active site and facilitate ion transport. Simultaneously, MXene effectively enhances the conductivity of the heterostructure, resulting in accelerating electron transport. Due to these attributes, the P-Bi-ene/MXene heterostructure demonstrates high desalination capacity (90.0 mg/g), fast desalination rate, and good cycling performance. The simple self-assembly strategy between 2D/2D materials described herein may offer inspirations for the synthesis of innovative electrode materials with high performance.

Coating CoFe2O4 shell on Fe particles to increase the utilization efficiencies of Fe and peroxymonosulfate for low-cost Fenton-like reactions.

Bimetallic composites (Fe@CoFe2O4) with zero-valent Fe as the core encapsulated by CoFe2O4 layers are synthesized by a coprecipitation-calcination method, which are applied to activate PMS for the degradation of bisphenol A (BPA). Enhanced activity of Fe@CoFe2O4 is achieved with very fast degradation rate (kobs = 0.5737 min-1). In the fixed-bed reactor, the catalyst lifetime (tul) of Fe@CoFe2O4 is determined to be 22 h compared to 11 h of Fe, and the deactivation rate constant (kd) for Fe@CoFe2O4 is 0.0083 mg·L-1·h-1, only ∼1/10 of Fe (0.0731). The XPS results indicate that the core-shell structure of Fe@CoFe2O4 could promote the redox cycles of Co3+/Co2+ and Fe3+/Fe2+. It is proved that the coating of CoFe2O4 shell on Fe0 can protect the Fe0 core from being oxidized by PMS to form passivation layer. The electrons of Fe0 can therefore be used effectively for activating PMS to produce ROSs via the CoFe2O4 shell. This modification method of Fe0 would decrease the cost of PMS based wastewater remediation greatly, thus should have great potential on an industrial scale.

Freestanding defective ammonium Vanadate@MXene hybrid films cathode for high performance aqueous zinc ion batteries.

Aqueous zinc ion batteries (AZIBs) have gained extensive attention due to the numerous advantages of zinc, such as low redox potential, high abundance, low cost as well as high theoretical specific capacity. However, the development of AZIBs is still hampered due to the lack of suitable cathodes. In this work, the freestanding defective ammonium vanadate@MXene (d-NVO@MXene) hybrid film was synthesized by simple vacuum filtration strategy. Due to the presence of the hierarchical freestanding structure, outstanding MXene conductive networks and abundant oxygen vacancy (in the d-NVO nanoribbons), the d-NVO@MXene hybrid film can not only expose more active sites but also possess outstanding conductivity and kinetics of charge transfer/ion diffusion. When the d-NVO@MXene hybrid film was directly used as the cathode, it displayed a high specific capacity of 498 mAh/g at 0.5 A/g and superior cycling stability performance with near 100 % coulomb efficiency. Furthermore, the corresponding storage mechanism was elucidated by ex situ various characterizations. This work provides new ideas for the development of freestanding vanadium-based cathode materials for AZIBs.

MoO2 Nanoclusters Embedded in Hierarchical Nitrogen Doped Carbon Nanoflower as Electrocatalytic Mediators in Aqueous Zinc-Tellurium Batteries: Enhancing Electrochemical Kinetics of Tellurium Redox Reaction.

Aqueous zinc-ion batteries (AZIBs) are considered to be one of the most promising devices for large-scale energy storage systems owing to their high theoretical capacity, environmental friendliness, and safety. However, the ionic intercalation or surface redox mechanisms in conventional cathode materials generally result in unsatisfactory capacities. Conversion-type aqueous zinc-tellurium (Zn-Te) batteries have recently gained widespread attention owing to their high theoretical specific capacities. However, it remains an enormous challenge to improve the slow kinetics of the aqueous Zn-Te batteries. Here, MoO2 nanoclusters embedded in hierarchical nitrogen-doped carbon nanoflower (MoO2 /NC) hosts are successfully synthesized and loaded with Te in aqueous Zn-Te batteries. Benefitting from the highly dispersed MoO2 nanoclusters and hierarchical nanoflower structure with a large specific surface area, the electrochemical kinetics of the Te redox reaction are significantly improved. As a result, the Te-MoO2 /NC electrode exhibits superior cycling stability and a high specific capacity of 493 mAh g-1 at 0.1 A g-1 . Meanwhile, the conversion mechanism is systematically explored using a variety of ex situ characterization methods. Therefore, this study provides a novel approach for enhancing the kinetics of the Te redox reaction in aqueous Zn-Te batteries.

Strong interface coupling boosting hierarchical bismuth embedded carbon hybrid for high-performance capacitive deionization.

Capacitive deionization (CDI) is regarded as a promising desalination technology owing to its low cost and environmental friendliness. However, the lack of high-performance electrode materials remains a challenge in CDI. Herein, the hierarchical bismuth-embedded carbon (Bi@C) hybrid with strong interface coupling was prepared through facile solvothermal and annealing strategy. The hierarchical structure with strong interface coupling between the bismuth and carbon matrix afforded abundant active sites for chloridion (Cl-) capture, improved electrons/ions transfer and the stability of the Bi@C hybrid. As a result of these advantages, the Bi@C hybrid showed a high salt adsorption capacity (75.3 mg/g under 1.2 V), salt adsorption rate and good stability, making it a promising electrode material for CDI. Furthermore, the desalination mechanism of the Bi@C hybrid was elucidated through various characterizations. Therefore, this work provides valuable insights for the design of high-performance bismuth-based electrode materials for CDI.

H2O2 activation and contaminants removal in heterogeneous Fenton-like systems.

Emerging contaminants can be removed effectively in heterogeneous Fenton-like systems. Currently, catalyst activity and contaminant removal mechanisms have been studied extensively in Fenton-like systems. However, a systematic summary was lacking. This review summarized: 1) The effects of various heterogeneous catalysts on emerging contaminants degradation by activating H2O2; 2) The role of active sites in different catalysts during the activation of H2O2 and their contribution to the generation of active species; 3) The modulation of degradation pathways of emerging contaminants. This paper will help scholars to advance the controlled construction of active sites in heterogeneous Fenton-like systems. Suitable heterogeneous Fenton catalysts can be selected in practical water treatment processes.

Hierarchical amorphous vanadium oxide and carbon nanotubes microspheres with strong interface interaction for Superior performance aqueous Zinc-ion batteries.

Aqueous zinc-ion batteries have attracted more and more attention due to their safety, environmental benignity and high theoretical capacity. However, the lack of appropriate cathode materials with high capacity and long cycle life have become an obstacle to the development of aqueous zinc-ion batteries. Herein, the hierarchical amorphous vanadium oxide and carbon nanotubes (a-V2O5@CNTs) microspheres with strong interface interaction were successfully prepared by combing facile spray drying technique with annealing treatment. Benefiting from the a-V2O5 amorphous characters, CNTs framework high conductivity and hierarchical microspheres with strong interface interaction, the a-V2O5@CNTs exhibited abundant active sites, fast reaction kinetics as well as eminent structure stability. As a promising electrode material, the a-V2O5@CNTs displayed high specific capacity (480 mAh g-1 at 0.5 A g-1), good rate capability and long-term stability under high current density (158 mAh g-1 at 30 A g-1 over 1000 cycles). Meanwhile, the corresponding mechanism was further illustrated through different characterizations. Furthermore, the as-assembled flexible pouch battery based on the a-V2O5@CNTs delivered outstanding flexibility and feasibility. Hence, this work provides a new idea for developing high performance cathode materials of aqueous zinc-ion batteries.

Role variations of MnOx on monoclinic BiVO4 (110)/(040) facets for enhanced Photo-Fenton reactions.

Compared with traditional Fenton reaction, peroxymonosulfate based advanced oxidation processes (PMS-AOPs) are more effective to remove the organic pollutants in wastewater in a wider pH range. Herein, selective loading of MnOx on monoclinic BiVO4 (110) or (040) facets were achieved by photo-deposition method with addition of different Mn precursors and electron/hole trapping agents. MnOx has good chemical catalysis activity for PMS activation, which can also enhance photogenerated charge separation, thus leading to enhanced activities than naked BiVO4. The BPA degradation reaction rate constants of MnOx(040)/BiVO4 and MnOx(110)/BiVO4 system are 0.245 min-1 and 0.116 min-1, which are 6.45 and 3.05 times larger than that of naked BiVO4, respectively. The roles of MnOx on different facets are different, which will promote OER process on (110) facets and utilize the dissolved O2 to produce O2•- and 1O2 more effectively on (040) facets. 1O2 is the dominated reactive oxidation species of MnOx(040)/BiVO4, while SO4•- and •OH play more important roles on MnOx(110)/BiVO4, which are proved by quenching experiments and chemical probe identifications, thus mechanism in MnOx/BiVO4-PMS-light system is proposed. The good degradation performance of MnOx(110)/BiVO4 and MnOx(040)/BiVO4 and mechanism theory may promote the application of photocatalysis in PMS based wastewater remediation.

Tunable Pt-Ni Interaction Induced Construction of Disparate Atomically Dispersed Pt Sites for Acidic Hydrogen Evolution.

Developing cost-effective Pt-based electrocatalysts for the hydrogen evolution reaction (HER) is highly urgent. Herein, we report novel electrocatalysts with individually dispersed Pt active sites and tunable Pt-Ni interaction decorated on carbon-wrapped nanotube frameworks (Pt/Ni-DA). Pt/Ni-DA exhibits superior HER performance at low Pt concentrations with an ultralow overpotential of 18 mV at 10 mA cm-2 and an ultrahigh mass activity of 2.13 A mgPt-1 at an overpotential of 50 mV, which is about four times higher than that of commercial Pt/C. X-ray absorption fine structure (XAFS) confirms the extension of Pt from the Ni surface to the Ni bulk phase. Mechanistic research and density functional theory (DFT) calculations collectively reveal that the dispersibility and distribution of Pt atoms in Ni regulate the electronic configuration of Pt sites, optimizing the binding energy of reaction intermediates and facilitating electron transfer during the HER process. This work highlights the importance of the electronic structure alternation through the accommodation effect toward enhanced catalytic performance in HER.

Enhanced redox cycle of Fe3+/Fe2+ on Fe@NC by boron: Fast electron transfer and long-term stability for Fenton-like reaction.

In this work, Fe@NC/B material is successfully synthesized and in-situ supported on the surface of amorphous boron (B) using a simple pyrolysis method. The interface between Fe species and B is improved by introducing N-doped carbon (NC) layers as intermediate, fast electron transfer from B to Fe@NC can therefore be achieved, thus could promote the fast redox cycle of Fe3+/Fe2+. The obtained material can therefore activate peroxymonosulfate (PMS) effectively to degrade Bisphenol A (BPA), a fast degradation rate and a very long lifetime in a continous tubular reactor are realized. Moreover, experiments and DFT calculation indicate that Fe2+ containing species are the dominated active sites, while the exposed B atoms and structure defect of B can also activate PMS directly to produce SO4•- and 1O2 species for BPA degradation. In addition, boric acid is the oxidation product of B, which can be dissolved into the aqueous solution and expose fresh B species again for PMS activation. The combination of B with Fe@NC provide novel materials for long term PMS activation, thus could promote the real application of persulfates on an industrial scale.

Electro-reduction induced fast metal redox cycle on Co3O4-CuO@CNTs/Copper foam cathode for enhanced Fenton-like reaction.

In this study, free-standing Co3O4-CuO/CF electrodes are synthesized via an electrodeposition-annealing process and then protected by dip-coated carbon nanotubes (CNTs). The obtained Co3O4-CuO@CNTs/CF is employed as cathode to activate peroxymonosulfate (PMS) for the degradation of Bisphenol A (BPA) in an electrochemical system. The electrochemical assistant (EA) plays a critical role to accelerate metal redox by donating electrons sustainably, and the fast regeneration of Co2+/Cu+ could be achieved to promote chemical-catalysis for PMS activation, which is proved via the pre-electroreduction treatment. The rate constant of Co3O4-CuO@CNTs/CF/PMS system with EA is âˆ¼ 4.4 times compared to the system without EA. It also exhibits an excellent stability, which could still remove over 90% of BPA after eight cycles in 45 min. In addition, the coating of CNTs could decrease leaching of metals effectively. According to quenching tests and electron spin-resonance spectroscopy (ESR), the presence of EA could enhance the radical route by producing more SO4•- and •OH greatly, which is also proved by much faster degradation of carbamazepine (CBZ) and atrazine (ATZ) than that without EA. This work reveals activation mechanism of PMS in the electrochemical system, and provides an effective strategy to achieve the fast metal redox cycle for effective and long-term pollutant degradation.

Complete reconstruction of NiMoO4/NiFe LDH for enhanced oxygen evolution reaction.

The oxygen evolution reaction (OER) is a vital half-reaction in several electrochemical energy conversion devices. Herein, we report a hierarchical NiMoO4/NiFe LDH pre-catalyst that enables complete reconstruction and fine structural inheritance, while exhibiting a low overpotential of 188 mV at 10 mA cm-2 in 1.0 M KOH.

Vertically Aligned Bismuthene Nanosheets on MXene for High-Performance Capacitive Deionization.

Capacitive deionization has been considered as a promising solution to the challenge of freshwater shortage due to its high efficiency, low environmental footprint, and low energy consumption. However, developing advanced electrode materials to improve capacitive deionization performance remains a challenge. Herein, the hierarchical bismuthene nanosheets (Bi-ene NSs)@MXene heterostructure was successfully prepared by combining the Lewis acidic molten salt etching and the galvanic replacement reaction, which achieves the effective utilization of the molten salt etching byproducts (residual copper). The vertically aligned bismuthene nanosheets array evenly in situ grown on the surface of MXene, which not only facilitate ion and electron transport as well as offer abundant active sites but also provide strong interfacial interaction between bismuthene and MXene. Benefiting from the above advantages, the Bi-ene NSs@MXene heterostructure as a promising capacitive deionization electrode material exhibits high desalination capacity (88.2 mg/g at 1.2 V), fast desalination rate, and good long-term cycling performance. Moreover, the mechanisms involved were elaborated by systematical characterizations and density functional theory calculations. This work provides inspirations for the preparation of MXene-based heterostructures and their application for capacitive deionization.