Search

In this work, pulse electrodeposition method was proposed to directly deposit amorphous carbon coating (ACC) onto 316L stainless steel substrate in choline chloride-ethylene glycol deep eutectic solvent (DES) mixed with ammonium chloride (NH 4 Cl) to fabricate bipolar plates. The obtained dense ACC has a thickness of ∼400 nm. Potentiodynamic and potentiostatic polarization tests demonstrated that the corrosion current density of ACC coated 316L steel was of the order of 10−7 A cm−2 in the simulated proton exchange membrane fuel cells (PEMFC) working environment, and the self-corrosion potential of the coating positively shifted by 0.4V, indicating a significant improvement on corrosion resistance of the coated steel plate due to excellent electrochemical stability of ACC. The Rockwell C indentation test showed that the as-obtained ACC was strongly bonded to the substrate and also had high in-plane strength. Further numerical simulation and comparison experiments showed that C was chemically bonded with Fe in the substrate, which was boosted by the assistance of NH 4 Cl. The intact and strong bonding between ACC and the substrate is highly helpful to improve corrosion resistance. The success in coating stainless steel plate with ACC by pulse electrodeposition method provides a promising alternation for coating of proton exchange membrane electrolyzer cell (PEMEC) and PEMFC metal bipolar plates. • Amorphous carbon coating (ACC) has prepared by electrodeposition on 316LSS. • The ACC was strongly bonded to the substrate and had high in-plane strength. • With the assistance of NH 4 Cl, C was chemically bonded with Fe in the substrate. [ABSTRACT FROM AUTHOR]

[Display omitted] • Environmentally-friendly one-step novel method for producing rGO films. • Scale production of high-quality rGO thin films. • Applications in flexible transparent conductive films and supercapacitor electrodes. • Investigation of GO reduction mechanism, achieving valuable insights. The reduced graphene oxide (rGO) thin films have attracted much attention in flexible electronic devices and supercapacitors (SCs). However, the chemical reduction mechanism of GO needs to be clarified, and the one-step process at low temperatures for preparing high-quality rGO thin films from GO dispersions is still blank in the research field. Here, we propose a one-step operation to spray GO dispersions onto substrate or current collector under a hydroiodic acid (HI) atmosphere while simultaneously achieving the preparation of rGO thin films. This pioneering metal-free, transfer-free, fast, low-temperature, environmentally friendly, and scalable spraying technology enables large-scale production of high-quality rGO. This method realizes the preparation of highly conductive and high transmittance rGO thin films on flexible polyimide and polyethylene terephthalate substrates, as well as the preparation of rGO thin films on current collectors as SCs electrodes. Density functional theory calculations show that oxygen-containing functional groups on the surface of GO exhibit a stronger adsorption energy for HI, and have a low energy barrier during reduction by HI. Ab initio molecular dynamics simulated the possible reduction reaction path between GO and HI at 90 °C, demonstrating that HI molecules can effectively reduce GO. Furthermore, the sheet resistance of the transparent conductive film created using the method developed in this study reaches approximately 1000 Ω/sq (80 % transparency), and the specific capacitance of the SCs electrode film created in this method is 433.2 F/g (5 mV/s, 1 M H 2 SO 4). Our study not only validates the efficacy of the one-step synthesis method for rGO thin films but also provides theoretical insights into the underlying reaction mechanism. This work holds significant promise for advancing applications in various electronics by facilitating large-scale production of high-quality rGO thin films. [ABSTRACT FROM AUTHOR]

Superhydrophobic conversion coatings have attracted increasing attention in corrosion protection field due to their exceptional water-repellent properties. However, the retention of protective properties with surface wettability dynamics remains a significant challenge. Herein, a superhydrophobic coupling cerium coating with hierarchical structure is fabricated via cerium-doped deep eutectic solvent pretreatment and modification to extend corrosion resistance duration. The synergistic enhancement between hydrophobicity and active protection can significantly improve the anti-corrosion characteristics of magnesium alloys, resulting in a decrease in corrosion current density by an order of magnitude. The superhydrophobic surface can prevent the metal from corrosive media by reducing the contact area and thus slow down the corrosion rate. The cerium compound within the coating can form a cerium protective layer during the corrosion reaction of magnesium alloy, inhibiting the further corrosion process. Furthermore, the density functional theory (DFT) calculation revealed the corrosion protection mechanism of superhydrophobic coatings. Combining experimental investigations with theoretical calculations, this work provides a new strategy for enhanced anti-corrosion protection of superhydrophobic coatings. • A novel superhydrophobic coupling cerium conversion coating was designed by combining the cerium hierarchical structure with the superhydrophobic surface. • The cerium hierarchical structure was prepared cerium-doped deep eutectic solvent pretreatment. • The coating consists of an active protective primer and a superhydrophobic topcoat. • The corrosion mechanisms are explained through experimental studies, analytical insights, and DFT calculations. [ABSTRACT FROM AUTHOR]

An unconventional spheric quasi-SEI film is strategically configured on cost-effective red phosphorus. Highly activated surface with weakened P P bond strength and strengthened binding force increase the electrode integration. [Display omitted] • A method for moderate phosphorylation and etching of phosphorus surface. • An unconventionally spheric quasi-SEI film forms before lithiating progress. • Balls change from solid core–shell structure to hollow core–shell sphere structure. • Highly activated surface with weakened P P bond strength. • Highly activated surface strengthened binding force of PVdF. Solid electrolyte interface (SEI) film is the most important separation layer between nonaqueous electrolytes and anodes to protect anode from corrosion and maintain continuous ionic diffusion tunnels. However, SEI film, especially for high-capacity anode materials, is still confined to continuous and stable ionic conductive layer despite the conventional SEI film is intrinsically poor to resist against the drastic volumetric changes of active centers. Herein, an unconventional spheric quasi-SEI film is thus strategically configured on cost-effective red phosphorus electrode materials by moderate phosphorylation combined with pore-forming process. Microstructure adjustment from solid microspheres structure to hollowed core–shell spheres is visibly taken place on this amazing spheric quasi-SEI film during the stabilization. Benefiting from the highly activated surface with weakened P P bond strength and the strengthened binding force between phosphorus and binders, the optimized phosphorus anode presents an outstanding long-term durability with a high discharge capacity of 1126.4 mAh/g over 400 cycles at 200 mA g−1 even at a high phosphorus load ratio of 70 wt%. This revolutionary configuration of quasi-SEI film provides high-capacity anode materials subject to large volumetric changes an unconventional approach from dependence on conductive framework/matrix. [ABSTRACT FROM AUTHOR]

The CuF 2 @CoPPc lamellar hybrid was prepared by the recrystallization of CoPPc on the surface of CuF 2. This configuration can efficiently prevent CuF 2 from contacting directly with electrolyte and improve the reaction activity by weakening the bonding strength of Cu-F. CoPPc can catalyze the invertibility and surface reaction of CuF 2 , resulting in long cyclability, high capacity and high reversibility. [Display omitted] • A new strategy of tailoring the intrinsic Cu-F bond strength of CuF 2 is introduced to improve its durable reversibility. • As a catalyst, CoPPc enhances and improves the reversibility and surface reaction of CuF 2. • The synergistic effect of CuF 2 and CoPPc drastically promotes the charge transfer kinetics of the composite. • CuF 2 @CoPPc has long cyclability, high capacity and high reversibility. CuF 2 is a promising candidate of electrode materials for lithium-ion batteries due to its high specific capacity, high power density and environmental friendliness. However, the irreversible phase conversion and sluggish kinetics caused by serious copper dissolution and low conductivity make CuF 2 difficult to achieve long cycling life. A facile strategy to incorporate CoPPc into CuF 2 was proposed firstly to regulate the Cu-F bonding force to realize the high reversibility of CuF 2 for lithium-ion storage. The results of DFT calculation, differential charge density simulation, work function calculation and COHP bond level calculation show that the existence of CoPPc can improve the surface charge distribution of CuF 2 and thus improve the reversibility for durable lithium-ion storage. The cycle life performance of the CuF 2 @CoPPc composite electrode obtained by this method reached staggering 500 cycles and the capacity remained at 594.8 mAh/g. [ABSTRACT FROM AUTHOR]

Ionic liquid has become an important new type of solvent, not only with important developments in the field of environmental protection, but also with great potential in the preparation of functional materials. In this work, preparation of nano nickel-cobalt (Ni–Co) alloys with preferred orientation by deposition method in choline chloride-urea (CU) ionic liquid. The results show that metal ions were complexed with Urea in CU. The reduction region of Ni–Co alloy located at −0.6 ∼ −1.2 V. The redox type of Ni–Co alloy in CU solution was irreversible and the nucleation mechanism of Ni–Co alloy was three-dimensional (3D) instantaneous nucleation. By controlling the deposition potential, it can not only effectively change the cobalt content, micro-structure and crystallite size of the Ni–Co alloy, but also influence the preferred orientation of the Ni–Co alloy on the (220) crystal plane. In addition, the Ni–Co alloy has excellent corrosion resistance which was prepared from the CU system. • The electrocrystallization of Ni–Co alloy is 3D-instantaneous nucleation mechanism. • The first time to prepare nano Ni–Co alloys with preferred orientation on (220) crystal planes. • Deposition potential can control the Co content and microstructure of Ni–Co alloy. • Ni–Co alloy coating prepared by potentiostatic has excellent corrosion resistance. [ABSTRACT FROM AUTHOR]

• Ni-Co alloy coating prepared by potentiostatic has excellent corrosion resistance. • The electrochemical behavior of Ni-Co alloys in ionic liquids. • The electrocrystallization of Ni-Co alloy is 3D-instantaneous nucleation mechanism. • Deposition potential can control the Co content and microstructure of Ni-Co alloy. In this work, nickel-cobalt (Ni-Co) alloy was prepared in choline chloride-ethylene glycol deep eutectic solvent by deposition. Metal ion complex structure and stability were studied using UV–Vis. The electrochemical behavior in different metal salts was studied by voltammetry (CV) and chronoamperometry (CA). The corrosion resistance was studied using potentiodynamic polarisation and electrochemical impedance (EIS). Surface and phase composition of Ni-Co alloy coatings were characterized by scanning electron microscopy (SEM/EDS) and X-ray diffraction (XRD). The results from the voltammetry showed that the reduction peak appear among −0.6 V ∼ −1.13 V, which belonged to Ni-Co codeposition. The reduction of Ni-Co alloy in the CE was an irreversible process under diffusion control. Chronoamperometric results indicated that the electrodeposition of Ni-Co on a glassy carbon electrode followed the mechanism of instantaneous nucleation and three-dimensional growth. The results of microstructure and phase composition showed that the control of deposition potential could effectively control the microstructure and Co content of Ni-Co alloy. Nano crystal structure could be obtained with a grain size in the range of 3.1–4.0 nm. Comparison in the corrosion behaviour of the coatings showed that the change of Co content had an effect on the corrosion resistance of Ni-Co alloy. [ABSTRACT FROM AUTHOR]

The traditional MoSe 2 anode material for lithium-ion batteries has poor cyclic stability and relatively low capacity, which hinders its practical application. Herein, high capacity of Si and Se are exploratively incorporated into two-dimensional MoSe 2 nanopetals to configure Se@MoSe 2 /Si composite. The optimized Se@MoSe 2 /Si composites have both high capacity and good electrochemical stability with a high retention capacity of 1187.7 mAh/g after 200 cycles at 100 mA/g current density. The visible depression on volumetric expansion is observed on the configuration of Se@MoSe 2 /Si. The admirable function of silicon on the enhancement of the electrochemical activity and the conductivity of Se@MoSe 2 is theoretically demonstrated by First-principles calculations. This mutually beneficial interaction between the components demonstrates a promising synergistic effect on Se@MoSe 2 /Si. [ABSTRACT FROM AUTHOR]

• Si@MnO/C with cyclically formed interface triggers an interesting complementary effect. • Intimate interface contact enables high mechanical stability. • Mediated pseudo-capacitance is induced by the configuration of Si@MnO/C. • Si@MnO/C presents excellent cyclability and rate performance. Silicon has been focused as a potential candidate in practical lithium-ion batteries due to its amiable feature of high theoretical specific capacity and environmental friendliness. However, its long-term stability requires further improvements for the significant volumetric expansion during lithium insertion. A novel strategy of a complementary effect created by the special extra lithium-storage capability of transition metal oxides is proposed and explored for the modification of silicon in the study. Si@MnO/C composite with highly compact structure is thus prepared by a facile electrostatic process combined with heat treatment. The results demonstrate that the strategical introduction of ultrafine MnO plays a crucial role in the generation of the complementary effect, which outstandingly enhances the durability as well as the kinetics of silicon anode. A reversible capacity of 1085.7 mAh g−1 with a Coulombic efficiency over than 99% has been obtained after 500 cycles at the current density of 200 mA g−1. Even at a high current density of 2000 mA g−1, a retention capacity of 946.3 mAh g−1 could be maintained after 920 cycles. [ABSTRACT FROM AUTHOR]

[Display omitted] • CoPPc@SnO 2 hybrid with high-compact mechanical interface was successfully prepared. • Outstanding interface pseudo-capacitive effect was triggered. • Extra Li-ion interface storage capability has been demonstrated. • The kinetics is enhanced due to improved pseudo-capacitive effect. Extra interface capacity derived from the surface pseudo-capacitive effect has been widely reported and considered an important role in enhancing excellent kinetics in the system of transition metal oxides. However, outstanding pseudo-capacitive effect is seldom found in other kind of oxides or systems. In this work, we strategically use cobalt phthalocyanine decorated tin oxide nanotubes to fabricate CoPPc@SnO 2 amorphous/polycrystalline composite with enhanced extra lithium-ion storage capability. Amazing interface Li-ion storage in the configured CoPPc@SnO 2 is successfully triggered, and outstanding pseudo-capacitive effect is demonstrated as an important factor to improve the overall capacity as well as kinetics of the composite electrode. The reversible capacity of CoPPc@SnO 2 could be maintained to 950 mA h g−1 after 400 cycles, comparing with 500 mA h g−1of CoPPc and 250 mA h g−1 of SnO 2 under the same conditions. [ABSTRACT FROM AUTHOR]

Red phosphorus for lithium-ion batteries (LIBs) is considered to be promising electrode material due to the high theoretical capacity and moderate working potential. However, the enormous volumetric expansion and intrinsic poor electrical conductivity result in poor interfacial stability and sluggish reaction kinetics. Herein, different functional conductive polymers are introduced to modify the interface, aiming to improve the interfacial compatibility and mechanical stability between red phosphorus and matrix materials. The Cobalt polyphthalocyanine (CoPPc)/polydopamine (PD) hybrid interface not only facilitates electron transfer within the system, but also accommodate the volume expansion of red phosphorus. Consequently, the novel P/CoPPc@PD anode achieves a stable specific capacity of 650 mAh g−1 after 580 cycles at 200 mA g−1, and a discharge capacity of 385 mAh g−1 at 5.0 A g−1 even after 10,000 cycles, demonstrating outstanding long-term cycling stability and rate performance. The synergistic interfacial effects of CoPPc and PD not only improve the conductivity of the anode material, but also constructs a mechanical buffering layer for the volume expansion of phosphorus. Hence, the rational design strategy of P/CoPPc@PD anode for LIBs reveals excellent cycle stability and promising application. [Display omitted] • Inorganic/organic hybrid interface was configured for red phosphorus. • CoPPc can facilitate the electron transport of red phosphorus anode. • The PD elastic buffer layer can alleviate the volume change of red phosphorus. • The CoPPc@PD hybrid layer improves the kinetics and structural integrity. [ABSTRACT FROM AUTHOR]

• Nano-flake Ni-organic frame anchored Ni-porphyrins is configured. • Mechanical interface bridges between NiTPP and Ni-MOF. • The incorporation of NiTPP to MOF facilitates the charge transfer capability. • The composite yields a high-capacity retention of 840 mAh/g 200 cycles. Metal-organic framework materials (MOFs) have great potential as organic electrode materials for lithium-ion batteries due to their amiable porous structure and property tunability. However, the structure instability and poor electrochemical durability of MOFs hinders their application. An interesting metal–organic composite composed of Ni-MOF and Nickel (II) meso -Tetraphenylporphyin (NiTPP) is strategically proposed and configured in this study. The synergic integration of Ni-MOF and NiTPP presents a stable electrochemical cycling performance with a high retention capacity up to 840 mAh/g after 200 cycles, ascribed to the facilitation of the charge transfer capability and the diffusion kinetics. The configured metal–organic composites provide an explorative approach for organic alternatives for nonaqueous metal-ion batteries. [ABSTRACT FROM AUTHOR]

• The built-in electric field between the Mn 3 O 4 -MnS enhances the carrier transport. • The core–shell structure enables high mechanical stability. • Mediated pseudo-capacitance is induced by the configuration of Si@Mn 3 O 4 -MnS/C. • The vacancy-enriched Si@Mn 3 O 4 -MnS/C presents excellent cyclability. A configuring vacancy-enriched Mn oxide/sulfide embedded in amorphous carbon layer with highly concentrated vacancies to encapsulate silicon was tentatively explored to overcome the long-term stabilization issues of silicon active center. Our experimental results demonstrate that the configuration of vacancy-enriched Mn 3 O 4 -MnS/carbon hybrid coating layer not only functions as a physical separation layer to prevent silicon from direct contact with electrolytes, but also works as an interesting intermediator to facilitate the structure stabilization and the deep utilization of silicon core center. The surface pseudo-capacitive effect dramatically benefits to the modification of the rate performance of silicon. The synthesized Si@Mn 3 O 4 -MnS/C anode material maintains a high reversible capacity of 830 mAh/g after undergoing 200 charge–discharge cycles at 200 mA g−1 current density. [ABSTRACT FROM AUTHOR]

Graphite carbon for lithium-ion batteries (LIBs) has received extensive attention due to the strong stability and moderate working potential. In spite of these advantages, the intrinsic low theoretical capacity and the poor interface compatibility severely restrict the practical application of graphite carbon. Herein, a rational strategy to improve lithium storage performance of carbon derived from metal organic frameworks (MOFs) is constructively employed by decorating with red phosphorus. Because of the unique structure and properties, nickel MOFs-derived micro flower carbon matrix can not only provide more active sites for lithium storage, but also facilitate the performance of red phosphorus sites. Furthermore, the carbon decorated with red phosphorus (P/Ni@C) are tightly anchored by P-O-C bonds to provide a guarantee for the synergistic effect. The P/Ni@C anode delivers a high discharge capacity of 1184.6 mAh g−1 over 400 cycles at 200 mA g−1 and high-rate capacity of 686.8 mAh g−1 at 2000 mA g−1, which demonstrate excellent cyclic stability and charge transfer kinetics, respectively. [Display omitted] [ABSTRACT FROM AUTHOR]

The MnO/C@CoPPc composite is prepared by facile surface-vacancy filling engineering. CoPPc is strategically impregnated into the empty space among the needles of MnO/C and simultaneously coated on the surface of MnO/C micro-rods. This structure not only guarantee the active center of MnO/C from the direct contact with electrolytes, but also efficiently alleviate its conductive disconnection on cycling. The presence of CoPPc can also effectively inhibit the volume expansion of MnO. The MnO/C@CoPPc composite has high reversible capacity and high stability. [Display omitted] • CoPPc not only guarantee the active center of MnO/C from the direct contact with electrolytes, but also efficiently alleviate its conductive disconnection on cycling. • The configuration of CoPPc-impregnated MnO/C composite effectively improved the electrochemical performance of MnO/C. • CoPPc can effectively inhibit the volume expansion of MnO during the charge-discharge cycle. • The MnO/C@CoPPc composite has high capacity and high stability. MnO has the advantages of high theoretical capacity, abundant resources and environmental friendliness, which is a potential material for lithium-ion storage. However, severe volume expansion and sluggish kinetics make MnO difficult to maintain long-term stability. In this study, MnO/C@CoPPc micro-rods composed of coral-like MnO/C nanobundles coated with CoPPc was synthesized via facile method. CoPPc impregnated into the empty space and simultaneously coated on the surface of the needles of MnO/C functions as an elastic layer to accommodate the mechanical stress caused by volume expansion of MnO/C, and simultaneously function as a buffering layer to keep electric disconnection on cycling. The volume of MnO/C is dramatically suppressed from 370% to 120%, and the reversible capacity is improved. Therefore, the configured MnO/C@CoPPc exhibits a high stability and delivers a high reversible capacity of 679.6 mAh/g after 200 cycles. [ABSTRACT FROM AUTHOR]

A novel carbon-excluded strategy to achieve performance improvement of red phosphorus is constructively explored on a simple P/S composite via cyclically constructing a dynamic hetero-interface with built-in electric fields. [Display omitted] • Despite composed of only two electron insulating components, P/S composite has excellent performance. • Periodically formed transient interface is crucial for performance improvement. • Lithiated sulfur is crucial for the formation of transient hetero-interface. • The built-in electric field provides fast diffusion tunnels for ions and electrons. Red phosphorus has attracted tremendous attention because of its high theoretical specific capacity, cost effective as well as environmental friendly characteristics. Nevertheless, its large volumetric expansion during the charge–discharge process and intrinsic poor conductivity have severely hindered the practical application of red phosphorus. A novel strategy of carbon-excluded in active materials to achieve performance improvement of red phosphorus is constructively explored by delicate interface regulations of building a dynamic hetero-interface on cycling. A very simple red phosphorus/sulfur (P/S) was prepared by moderately ball-milling process to achieve the purpose despite only two electron-insulating components of sulfur (S) and red phosphorus (P) are involved. The experiment results demonstrate that the in-situ formation of the temporary solid sheath of lithiated sulfur, which is partially incorporated in solid electrolyte interface (SEI) film around red phosphorus. It is the crucial factor to depress the decomposition of the electrolyte. Furthermore, theoretic calculations based on first-principles reveal that the built-in electric field in the transient interface of Li 2 S/P provides fast diffusion tunnels for ions and electrons, which facilitates to improve the kinetics of the electrode. Our research demonstrates the construction of dynamic hetero-interfaces have huge potentials to improve the sluggish kinetics of high capacity electrode materials. [ABSTRACT FROM AUTHOR]