Research of the transition from a aqueous zinc ion battery to an aqueous hydrogen proton battery triggered by the Cu@Cu31S16 cathode material development.

The aqueous zinc ion battery (AZIB) has been widely studied due to its rapid kinetics and high specific capacity attributed to the chemical insertion of H+ protons. However, the current research landscape lacks comprehensive investigations into copper-based sulfide materials and the intricate co-embedding/extraction mechanism of H+/Zn2+. In this study, we employed an innovative in-situ etching method to synthesize a current collector-integrated Cu@Cu31S16 cathode material. Cu31S16 not only exhibits excellent stability and conductivity but also activates proton insertion chemistry. Consequently, we have demonstrated, for the first time, efficient and reversible co-embedding/extraction behavior of H+/Zn2+ in Zn-Cu31S16 batteries. Specifically, owing to the lower charging and discharging plateaus of zinc ions (0.65 V, 0.45 V) compared to H+ (0.97 V, 0.84 V) in Zn-Cu31S16 batteries, two distinct plateaus were observed. Moreover, we delved into the mechanism of ion co-embedding/extraction by exploring different ions (Zn2+, H+/Zn2+, H+) within varying voltage ranges. This exploration led to the development of three types of ion batteries, where Zn2+, H+/Zn2+, and H+ exhibit co-embedding/extraction within voltage ranges of 0.3-0.9 V, 0.3-1.05 V, and 0.5-1.05 V, respectively. These batteries have achieved impressive performance with specific capacities of 282.74 mAh g-1, 587.4 mAh g-1 and 687.3 mAh g-1, respectively. Introducing the concept of "Voltage-Selective Ion Co-Embedding/Extraction", this study broadens the research scope of AZIBs. This research not only offers a feasible solution and theoretical guidance for future proton batteries but also underscores the tremendous potential of AHPB.

Hydrogen Bond Interaction in the Trade-Off Between Electrolyte Voltage Window and Supercapacitor Low-Temperature Performances.

Liquid electrolyte determines the voltage window and extreme working temperature of supercapacitors. However, the effect of weak interaction between electrolyte species on voltage window and low-temperature capacitive performance is unclear. Herein, an electrolyte model system with increasing H-bond interaction was constructed to clarify this concern. The results indicated that strong H-bond interaction was positively correlated with the number of hydroxyls, which was beneficial to expand voltage window, but deteriorated rate performance; weak H-bond improved low-temperature performance. Supercapacitors with an optimized electrolyte presented high voltage and good low-temperature performance; even at -40 °C, the maximum energy density could be maintained at 7.0 Wh kg-1 (>80 % retention relative to at -20 °C). This study revealed the mechanism of the influence of the H-bonds on electrolyte voltage window and anti-freezing capability and provided a new insight for the design of electrolytes with both high working voltage and low-temperature performance.

Cerium Oxysulfide with O-Ce-S Bindings for Efficient Adsorption and Conversion of Lithium Polysulfide in Li-S Batteries.

Understanding of adsorption and kinetic conversion of polysulfide lithium (LiPSs) in Li-S batteries is quite crucial for the design of efficient effective sulfur carriers. Herein, based on the possible interactions with LiPSs, Ce2O2S with unique O-Ce-S bindings is proposed to be used as a promising carrier additive and a 2D Ce2O2S/C composite is synthesized via a one-facile NaCl-template method and subsequent sulfuration under 700 °C. The 2D Ce2O2S/C exhibits a stronger adsorption capability than CeO2/C through the adsorption test for Li2S6. Combined with XPS and DFT results, the superiority is mainly originated from the formation of S-S and Li-S bonds between LiPSs and the lattice S on the surface of Ce2O2S. The 2D Ce2O2S/C composite also exhibits a better catalytic ability than CeO2 according to the change of the free energies of the polysulfides during the discharge process, which coincides with the lower oxidation potential for Li2S2/Li2S transition by cyclic voltammetry. Resultantly, the cathodes using the Ce2O2S/C composite as a carrier manifest an enhanced rate and cycling performances. Hence, our work paves a phenomenon wherein Ce2O2S with O-Ce-S bindings is more beneficial to improve the cycling stability of Li-S batteries than CeO2 containing single Ce-O bonds, which may be also suitable for other kinds of metallic sulfur oxide compounds.

Crystalline coordination polymer-derived MoS2 quantum dot-doped carbon nanoflakes with ultrafast Li+ transfer.

In this work, N and MoS2 quantum dot co-doped uniform 2D carbon nanoflakes are synthesized. Owing to its high quantum dot content of 54.56 wt%, the sample exhibits excellent rapid charging performance when used as an anode material in Li-ion batteries, even under a current density of 10 A g-1.

Unravel the Catalytic Effect of Two-Dimensional Metal Sulfides on Polysulfide Conversions for Lithium-Sulfur Batteries.

Despite extensive studies, the role of polar chemical interfaces on carrier materials anchoring polysulfide species remains an ambiguous but intriguing topic for lithium-sulfur batteries. Herein, to further investigate the effect of metal sulfides in the conversion of polysulfides, three kinds of MxSy (M = Cr, Mo, and W) are chosen and prepared in the forms of two-dimensional MxSy/C composites via a method using NaCl as a template and a subsequent high-temperature sulfuration process. Compared with a blank sample, the three composites exhibit superior adsorption of soluble polysulfides and faster kinetics of the deposition of Li2S2/Li2S, especially on Cr3S4/C and WS2/C. These differences in performances of the three composites are further evaluated by the values of the Gibbs free energy in each step of polysulfide conversion. In the conversion processes of Li2S4 to Li2S2 and then to Li2S, the values are more negative on Cr3S4 and WS2, showing stronger promotion abilities for the formation of Li2S than MoS2. This work can effectively deepen the role of metal sulfides in the conversion process of polysulfides and provide valuable insights into the design of superior carriers for lithium-sulfur batteries.

Crystal reconstruction of binary oxide hexagonal nanoplates: monocrystalline formation mechanism and high rate lithium-ion battery applications.

Structural design and/or carbon modification are the most important strategies to improve the performance of materials in many applications, where metal (oxide)-based anode design attracts great attention in metal ion batteries due to their high capacities. However, achieving these two goals within one-step remains challenging due to the lower cost and higher efficiency needed to satisfy the demand in practical application. Herein, we report a new approach for the crystal reconstruction of metal oxides by acetylene treatment, in which a hierarchical binary oxide decorated with carbon (i.e., Mn2Mo3O8@C) is introduced. The mechanism of constructing unique monocrystalline hexagonal nanoplates and uniform carbon coating is discussed in detail. Benefiting from the uniqueness of structure and composition, the Mn2Mo3O8@C demonstrates an extremely high lithium storage capacity of 890 mA h g-1 and good rate capacities at 20 A g-1 over 1000 cycles. In addition, the high rate capabilities and long cycle lifespan are further confirmed when the Mn2Mo3O8@C anode is matched with the nickel-rich layered oxide cathode. This study not only introduces a new binary oxide anode with high performances in lithium (ion) batteries but also presents a convenient methodology to design more advanced functional materials.

Metal-Organic Coordination Strategy for Obtaining Metal-Decorated Mo-Based Complexes: Multi-dimensional Structural Evolution and High-Rate Lithium-Ion Battery Applications.

Multi-dimensional metal oxides have attracted great attention in diverse applications due to their intriguing performances. However, their structural design remains challenging, particularly that based on organic chelation chemistry. Although metal-organic complexes with different architectures have been reported, their structure formation mechanisms are not well understood because of the complex chelation processes. Herein, we introduce a new metal-organic coordination strategy to construct metal-decorated (Ni, Co, Mn) Mo-based complexes ranging from 2D nanopetals to 3D microflowers. The chelating process of the metal-organic complex can be tuned by a surfactant, giving rise to different structures, and then a further metal can be appended. Thus, different metal (oxide)-decorated MoO2 /C-N structures were designed, enabling an extremely high lithium storage capability of 1018 mA h g-1 and rate capacities of up to 10 A g-1 over 1000 cycles. Relationships between electrochemical behavior and structure have been analyzed kinetically. A high-rate lithium-ion battery has been assembled from Ni-MoO2 /C-N and an Ni-rich layered oxide as the anode and cathode, respectively. We believe that this general metal-organic coordination strategy should be applicable to other multi-functional materials with superior capabilities.

Insight of Enhanced Redox Chemistry for Porous MoO2 Carbon-Derived Framework as Polysulfide Reservoir in Lithium-Sulfur Batteries.

As a promising energy-storage system, lithium-sulfur batteries (LSBs) with a high energy density suffer from the polysulfide shuttle effect and sluggish reaction kinetics, which have been studied for a few decades. Incorporation of polar metal oxides is an efficient addition for LSBs to suppress the dissolution of soluble polysulfides, increase the utilization of sulfur, and improve cycling stability. Herein, a model (MoO2/C-NCs) based on a porous octahedral carbon framework decorated with MoO2 nanoparticles (MoO2 NPs) as a sulfur host is proposed. Adsorption experiments of lithium polysulfides (LiPSs) to MoO2/C-NCs and cyclic voltammetry analysis showed that the MoO2 NPs facilitate interfacial charge transfer and provide numerous active sites for the electrochemical redox reactions of LiPSs. Density functional theory calculations further reveal that LiPSs are diffused and strongly adsorbed on the surface of MoO2 NPs because of the powerful van der Waals forces via Mo-S and Li-O bonds, which helps achieve a stable long-term cycling performance. As a result, the fabricated LSBs display a high initial specific capacity of 1317 mA h g-1 at 0.2C and a promising capacity of 602 mA h g-1 and a capacity retention of 65.6% at 1C when proceeding to 500 cycles.

Bioinspired Architectures and Heteroatom Doping To Construct Metal-Oxide-Based Anode for High-Performance Lithium-Ion Batteries.

The pursuit of increased energy density and longer lifespan lithium-ion batteries (LIBs) is urgently needed to satisfy a dramatically increased demand in the energy market. Currently, metal-oxide-based anodes are being intensively studied due to their higher capacities over current graphite anodes. This work introduces a sustainable strategy to construct a metal-oxide-based anode with high capacity and an extremely long lifecycle, in which the features of bioinspired architectures and heteroatom doping can contribute greatly to increased performances. In detail, 1D tubelike metal oxide (e.g., MnO) coated on an N-doped carbon framework (i.e. MnO/N-C) has been designed by using the naturally abundant and renewable Metaplexis japonica fibers (MJFs) as the biotemplate and heteroatom source. Benefiting from the uniqueness of structure and compositions, as-prepared MnO/N-C demonstrates extremely high rate capacities of 951, 777, 497, and 435 mAh g-1 at the rates of 0.5, 2, 4, and 5 Ag-1 , respectively, with a good stability of more than 1000 cycles. It was found that the electrochemical performances are superior to most previous MnO-based anodes, in which the faster kinetics of conversion due to the advantage of the ion/electron transportation and morphological evolution has been verified. It is hoped that the concept of bioinspired architectures with heteroatom doping can be applied in wider applications for increased capability.

Morphology Evolution and Control of Mo-polydopamine Coordination Complex from 2D Single Nanopetal to Hierarchical Microflowers.

Controllable synthesis of functional materials is of widespread interest for particle engineering. Such a method has not been widely promoted due to the lack of recognition of the fundamental principle, especially for organic-inorganic hybrid materials. Here, as an entrance, the controllable synthesis of Mo-polydopamine coordination flowers is realized through a facile foaming method, and a 2D nanopetal as the building monomer of the flower is synthesized. Depending on the morphology evolution of Mo-dopamine complex under different conditions, and the surface iterative topology growth of the Mo-polydopamine petal, the reasons of why the Mo-polydopamine complex self-assembles into a flower structure can be attributed to the synergistic effect of multicore symbiosis and structural self-protective growth behaviors. Benefiting from the strong structure stability of the Mo-polydopamine nanopetal, a hybrid structure of MoO2 quantum dot in situ anchoring in the N-doped 2D carbon framework is prepared by direct pyrolysis, which shows a highly reversible performance in application for lithium-ion secondary batteries (LIBs). This work enhances the possibility for the controllable synthesis of organic-inorganic hybrid materials by adjusting the multicore intergrowth and inhibiting the interfacial assembly.

A Kind of Coordination Complex Cement for the Self-Assembly of Superstructure.

Not like the macroscopic building materials, the controllable assembly of blocks into superstructure has not been conquered in microscale, especially for the ordinary particles with shape defects and weak surface activities. Here, a facile route of assembling particles into superstructures utilizing Mo-polydopamine complex as the binder and curing agent is established. A side-by-side adsorption and growth mechanism in a water/ethanol system is derived, and the factors influencing the final structures are verified. This system is suitable to assemble superstructures from particles of different shapes such as nanospheres, nanocubes, nanorods, and hollow spheres in the range from 10 to 500 nm in size. And after high temperature and etching treatment, the generated MoO2/N/C frameworks with superpore structures derived from different blocks exhibit a high structural plasticity and potential application as multifunctional carriers for energy storage. Rather than the obtained system, our work assembles superstructures from various building blocks and explores more valuable complex cements for superstructures construction.

High alkaline ion storage capacity of hollow interwoven structured Sb/TiO2 particles: the galvanic replacement formation mechanism and volumetric buffer effect.

A new galvanic replacement synthetic strategy using metallic Ti as a template for hollow voids is presented and an intriguing hollow interwoven structured Sb/TiO2 is introduced. The applied Ti can play the triple role of reducing the Sb-ion into Sb, acting as a sacrificial template to generate hollow voids through a structural evolution and behaving as an alternative non-sensitive titanium salt to form TiO2. Interwoven Sb/TiO2 can be readily activated and can also buffer drastic volumetric variations during storage of alkaline ions (e.g. Li+, Na+), thereby demonstrating high capacity and superior cycling ability in rechargeable batteries.

Large-Scale Fabrication of Core-Shell Structured C/SnO2 Hollow Spheres as Anode Materials with Improved Lithium Storage Performance.

Due to the high theoretical capacity as high as 1494 mAh g-1 , SnO2 is considered as a potential anode material for high-capacity lithium-ion batteries (LIBs). Therefore, the simple but effective method focused on fabrication of SnO2 is imperative. To meet this, a facile and efficient strategy to fabricate core-shell structured C/SnO2 hollow spheres by a solvothermal method is reported. Herein, the solid and hollow structure as well as the carbon content can be controlled. Very importantly, high-yield C/SnO2 spheres can be produced by this method, which suggest potential business applications in LIBs field. Owing to the dual buffer effect of the carbon layer and hollow structures, the core-shell structured C/SnO2 hollow spheres deliver a high reversible discharge capacity of 1007 mAh g-1 at a current density of 100 mA g-1 after 300 cycles and a superior discharge capacity of 915 mAh g-1 at 500 mA g-1 after 500 cycles. Even at a high current density of 1 and 2 A g-1 , the core-shell structured C/SnO2 hollow spheres electrode still exhibits excellent discharge capacity in the long life cycles. Consideration of the superior performance and high yield, the core-shell structured C/SnO2 hollow spheres are of great interest for the next-generation LIBs.

Formation of Mo-Polydopamine Hollow Spheres and Their Conversions to MoO2 /C and Mo2 C/C for Efficient Electrochemical Energy Storage and Catalyst.

Highly uniform hierarchical Mo-polydopamine hollow spheres are synthesized for the first time through a liquid-phase reaction under ambient temperature. A self-assembly mechanism of the hollow structure of Mo-polydopamine precursor is discussed in detail, and a determined theory is proposed in a water-in-oil system. Via different annealing process, these precursors can be converted into hierarchical hollow MoO2 /C and Mo2 C/C composites without any distortion in shape. Owing to the well-organized structure and nanosize particle embedding, the as-prepared hollow spheres exhibit appealing performance both as the anode material for lithium-ion batteries and as the catalyst for hydrogen evolution reaction (HER). Accordingly, MoO2 /C delivers a high reversible capacity of 940 mAh g-1 at 0.1 A g-1 and 775 mAh g-1 at 1 A g-1 with good rate capability and long cycle performance. Moreover, Mo2 C/C also exhibits an enhanced electrocatalytic performance with a low overpotential for HER in both acidic and alkaline conditions, as well as remarkable stability.

Self-Assembly of Hierarchical Ni-Mo-Polydopamine Microflowers and their Conversion to a Ni-Mo2 C/C Composite for Water Splitting.

With the aim of finding efficient non-noble metal catalysts for water splitting, hierarchical Ni-Mo-polydopamine microflowers (Ni-Mo2 C/C MF) were synthesized through a facile aqueous-phase reaction at room temperature. NiMoO4 nanowires were utilized as both Ni and Mo source; they can complex with dopamine to form a hierarchical structure and affect the scale of the final product. The energy dispersive spectroscopy (EDS) measurement of Ni-Mo2 C/C microflowers (MF) shows a high content of Mo2 C and Ni (>90 wt %). For the hydrogen evolution reaction (HER), the Ni-Mo2 C/C MF displays a low overpotential of 99 mV at a current density of -10 mA cm-2 and a small Tafel slope of 73 mV dec-1 in 1.0 m KOH. By comparison with Mo2 C/C microspheres (MS), the nanosized Ni-doped particles offer more active sites and enhance the kinetic performance. This facile synthesis strategy is also suitable for preparing other metal-Mo2 C/C composites that can be used in the fields of catalysis and energy conversion.

Desorption electrospray tandem MS (DESI-MSMS) analysis of methyl centralite and ethyl centralite as gunshot residues on skin and other surfaces.

A direct and sensitive method for the detection of methyl centralite (MC) and ethyl centralite (EC) as gunshot residues (GSRs) has been developed. This method uses desorption electrospray ionization (DESI)-tandem mass spectrometry and directly desorbs and detects analytes from surfaces without any sampling process. Typical transitions for MC and EC, m/z 241 to m/z 134 and m/z 269 to m/z 148, respectively, were used to improve the assay sensitivity. It has been shown that MC and EC can be detected on various surfaces, with detection limits of 5-70 pg/cm(2). Interferences, detection time after shooting and the number of times hands were washed after shooting were also evaluated. None of the materials interfered with the results and the detection window for organic GSRs was up to 12 h and hands could be washed at least six times. Further samples were analyzed to confirm the reliability of this method, and showed that it could discriminate shooters from nonshooters. This method should be of significance in forensic science, especially in analyzing GSRs, because of its simplicity, high throughput, and the direct detection of MC and EC on suspects' hands, clothes, and hair.