Electrochemical Hydrogen Storage Properties Research Articles

Palladium effect on electrochemical hydrogen storage properties of nanoporous silicon

Coating porous silicon with metal catalysts such as palladium is considered a reliable method to improve the hydrogen storage performance of electrodes. Here, in order to evaluate the most effective use of Pd nanoparticle or Pd thin film, Pd nanoparticles with a size of 36 nm obtained by electroless method, and a Pd thin film with a thickness of 30 nm deposited by thermal evaporation were coated onto nanoporous silicon sample” and studied. The Pd deposits were confirmed by Scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR). The obtained electrode materials: PS and Pd/PS were characterized by different electrochemical characterization techniques: cyclic voltammetry (CV) and galvanostatic charge/discharge. The results showed that Pd NPs/PS achieved the highest hydrogen storage capacity with a value of 425.9 mA h g-1. These results confirm that using Pd nanoparticles as catalyst metal is more suitable to improving the hydrogen storage capacity of electrode materials.

Characteristics of hydride electrodes using Mg-Ti-Ni-Co-Al-based alloys synthesized by mechanical milling

For Ni-MH batteries, crystalline Mg-based alloys such as MgNi, Mg2Ni, REMg12, and La2Mg17 are regarded as hopeful negative electrode materials. Even though these alloys are inexpensive and have promising discharge capacity, they hardly ever electrochemically absorb or desorb hydrogen at room temperature. In this paper, the MgNi-based Mg50-xTixNi45Al3Co2 (x = 0, 1, 2, 3, 4) alloy electrodes were fabricated. The surface of the as-cast alloys was modified by mechanical Ni coating. The nanocrystalline and amorphous Mg50-xTixNi45Al3Co2 (x = 0, 1, 2, 3, 4) + 50 wt%Ni alloys for Ni-MH batteries were prepared using mechanical ball milling. The effects of Ti content and ball milling time on the structure and electrochemical hydrogen storage properties of the alloys were investigated. The electrochemical testing reveals that the as-milled alloys can electrochemically absorb and desorb hydrogen well at room temperature. Without any activation, the milled alloys can achieve maximum discharge capacity in the first cycle. With the extension of ball milling time and the increase of Ti content, the cycle stability and discharge capacity of the alloys are significantly enhanced. The electrochemical impedance spectrum, high rate discharge ability, potentiodynamic polarization curve, and potential-step measurement all indicate that the electrochemical kinetics of the prepared alloys initially increase and subsequently decrease with the increase of Ti content, while significantly improve with the prolongation of milling time.

Effects of Mn and Fe elements on the electrochemical hydrogen storage properties of the A5B19-type La-Y-Mg-Ni-Al alloy for nickel metal hydride battery

Rare earth–Mg–Ni-based alloys with superlattice structures are novel anode materials for nickel metal hydride batteries, wherein A5B19-type alloys have been regarded as the replacement of the current commercialized A2B7-type alloys due to the superior discharge ability at high rates and cycling stability. However, it is still a challenge to further improve the hydrogen storage properties of the A5B19-type alloys in a low-cost approach. Herein, we select low-cost Mn and Fe elements to substitute Ni to further reduce the cost of an A5B19-type La0.72Y0.13Mg0.15Ni3.70Al0.15 alloy and focus on their effects on the alloy's structure and hydrogen storage properties. Results show that the La0.72Y0.13Mg0.15Ni3.65Al0.15Fe0.05 alloy features increased intrinsic gas-solid hydrogen storage ability of 1.44 wt% and hydrogen absorption enthalpy change of −22.9 kJ mol–1, which have been altered by 0.21 wt% and 7.3 kJ mol–1 in contrast to the La0.72Y0.13Mg0.15Ni3.70Al0.15 alloy, respectively. Furthermore, the Fe substitution benefits capacity retention during electrochemical cycling compared to Mn, which maintains 87.5% and 62.4% after cycling 100 and 500 times. The Mn substitution results in superior rate capability compared to the alloy containing Fe. The work provides guidance for designing hydrogen storage alloys with superlattice structures to improve the electrochemical performance.

Effect of ball milling on the structure and electrochemical hydrogen storage properties of a RE-Mg-Ni alloy

RE-Mg-Ni alloy is considered a highly promising anode material for the next generation of MH-Ni batteries. However, the low cycle life, fast performance, and high manufacturing cost of this ideal MH-Ni battery anode material have become obstacles to its optimization. In this work, an as-cast La0.7Sm0.3MgNi3.6Co0.4 superlattice alloy was prepared by vacuum medium frequency induction melting. Then, La0.7Sm0.3MgNi3.6Co0.4 + 10 wt% Ni (0–2 h) composite hydrogen storage alloys with excellent properties were prepared by adding a catalyst (Ni) and conducting ball milling. XRD, SEM, and HRTEM were conducted to analyse the phase compositions, microstructures and macrostructures of the samples. The experimental results showed that with the increase in ball milling time, the microstructural characteristics of the alloy changed, such as the phase abundance, grain refinement, particle size reduction, and amorphous structure increase, directly leading to the change in electrochemical performance. The discharge capacity (Cmax) of the sample decayed from 264.0 mAh/g to 219.1 mAh/g, the cycle stability (Sn) gradually increased with the extension of the grinding time, and the rate discharge performance first increased and then decreased. When the grinding time was 1 h, the best performance was HRD900 = 36.53%. The critical factors affecting the dynamic performance, such as the charge transfer resistance (Rct), limiting current density (IL), and hydrogen diffusion coefficient (D), all exhibited the same trend and reached their respective optimal values at 1 h.

Electrochemical capacitance and hydrogen adsorption behavior of activated carbon derived from cattail fiber

AbstractIn this paper, we have reported the synthesis of activated carbon (AC) from biomass cattail fiber through hydrothermal carbonization, followed by chemical activation, and its electrochemical capacitance and hydrogen storage properties. The AC exhibits a Brunauer‐Emmett‐Teller (BET) surface area (SBET) of 1597.5 m2g−1, determined from the low‐pressure N2 adsorption isotherm at 77 K using a BET‐multipoint plot. The AC sample shows a reversible hydrogen adsorption capacity of 0.25 wt.% H2 (1.25 mmol H2 g−1) at 293 K and 74 atm. The capacitance performance of AC was investigated with various conductive additives such as carbon nanotubes (CNTs), carbon black (CB), and reduced graphene‐oxide (rGO). From galvanostatic charge discharge (GCD) and cyclic voltammetry (CV) measurements, the as‐derived AC with polymer binder exhibits a specific capacitance (Cs) of 245.2 F g−1 at 0.2 A g−1 and 158.1 F g−1 at 5 mV s−1. Among the investigated conductive additives, AC with CNTs in KOH electrolyte exhibit highest Cs of 326 F g−1 at 0.2 A g−1 and 173 F g−1 at 5 mV s−1. Furthermore, the symmetrical two‐electrode device fabricated using AC with CNTs (as a conductive additive) in 1 M aq. Na2SO4 electrolyte shows a Cs of 97.2 F g−1 at 0.1 A g−1. The energy and power densities of the two‐electrode device were observed to be 28 kW kg−1 and 2.64 Wh kg−1, respectively.

Enhanced electrochemical hydrogen storage performance of Co9S8 material by doping with cobalt nanoparticles embedded hollow porous carbon nanofibers

Co-axial electrospinning has been regarded as an effective technology to fabricate hollow or core/shell nanofibers. Herein, co-axial electrospinning was carried out employing polymethyl methacrylate (PMMA) and polyacrylonitrile (PAN) as the core and shell components. Cobalt acetate was used as the cobalt source. The cobalt nanoparticles embedded hollow porous carbon fibers (Co/HCNF) were obtained after electrospinning and subsequent carbonization process. For comparison, the conventional carbon fibers (CNF), hollow carbon fibers (HCNF), and cobalt nanoparticles modified carbon fibers (Co/CNF) were also synthesized. Co9S8 material was manufactured via mechanical alloying. By adjusting the types of carbon fibers, a series of carbon fibers modified Co9S8 composites were obtained by ball milling and their electrochemical hydrogen storage properties were studied. As a result, the Co9S8 + Co/HCNF electrode showed the higher discharge capacity of 603.3 mAh/g than CNF, HCNF, Co/CNF modified Co9S8 and conventional Co9S8 electrodes. The Co nanoparticles within Co/HCNF provided high electrocatalytic activity. The special hollow porous structure and high specific surface area of Co/HCNF increased the conductivity, offered more electrochemical active sites and rapid channel for charge transfer. Moreover, Co9S8 + Co/HCNF also demonstrated improved high-rate dischargeability (HRD), capacity retention and kinetics properties. An advantageous solid-solid interface may be generated between Co9S8 and Co/HCNF, serving as a beneficial electron conduction path and facilitating the hydrogen diffusion, thereby enhancing the electrode performance of Co9S8 material.

Microstructure and electrochemical hydrogen storage properties of nanosized doped La2Ti2O7 solid solutions

Hydrothermal-sintering method was employed to obtain pure and Li, Co, Mn, Cu and Zn doped La2Ti2O7 solid solutions. The substitution sites of doping ions are discussed. X-ray diffraction (XRD) results indicate that the doped ions were incorporated into the lattice of La2Ti2O7 successfully. Transmission electron microscopy (TEM) measurements prove that the doped ions with smaller radius induce the contraction of lattice. The results of UV and photoluminescence (PL) tests show that the doped ions cause the red-shift of band gap energies and enhance the concentrations of oxygen vacancies and defects. The electrochemical hydrogen storage properties of the samples were measured at 303 and 333 K, respectively. The discharge capacities of the doped samples keep growing by increasing the cycle number at 333 K. Meanwhile, the doped samples possess better kinetic performances than the pure La2Ti2O7. Among the samples, the Mn, Co and Li ions doped samples exhibit better electrochemical hydrogen storage properties. The hydrogen storage properties are closely related with the characteristics of doped ions, crystallite sizes, the content of the oxygen vacancies and defects in the lattice of La2Ti2O7.

Synthesis of MOF derived porous cobalt/N-doped carbon polyhedrons for enhancing the electrochemical hydrogen storage properties of Co–P material

Employing metal-organic framework ZIF-67 as the precursor, the porous cobalt/N-doped carbon polyhedron (Co–CN) was synthesized via a facile high temperature carbonization process. Co–P material was synthesized through mechanical alloying. By adjusting the content of Co–CN and milling time, a series of Co–P + Co–CN composite electrodes were prepared to enhance the electrochemical hydrogen storage performance of Co–P. Ultimately, the electrode of 5 wt% Co–CN modified Co–P milling for 5 min attained the best discharge capacity of 590.4 mAh/g. The special porous structure and high specific surface area (SSA) of Co–CN derived from ZIF-67 could provide more electrochemical active sites. The nitrogen-doped carbon could further improve the conductivity of Co–P. After Co–CN polyhedrons modification, the HRD, capacity retention and kinetics properties were also enhanced. The Co–CN porous framework can serve as the active additive for designing the high-performance hydrogen storage materials.

Tuning phase structure and electrochemical hydrogen storage properties of A5B19-type La–Y–Ni–Mn-based superlattice alloys by partial Al substitution

Rare earth-based superlattice alloys are essential anodes for high-performance nickel-metal hydride (Ni-MH) batteries. This study aimed to improve the overall electrochemical hydrogen storage properties of (La0.33Y0.67)5Ni18.1-xMn0.9Alx alloys by adjusting the Al content. The alloys predominantly consist of the 2H–Pr5Co19 phase, with Al atoms mainly occupying the 12k2 site at the [AB5]-1/[AB5]-2 boundary and subsequently the 12k1 site at the [A2B4]/[AB5]-1 boundary. As a result, a minimum subunit volume difference of 2.08 Å3 is observed at x = 0.6. Therefore, the Al substitution is responsible for the decrease in the dehydriding plateau pressure and the increase in discharge capacity. Among them, the alloy (La0.33Y0.67)5Ni17.5Mn0.9Al0.6 presents a discharge capacity of 361.2 mAh/g, a higher capacity retention S200 of 69.80 %, and better rate performance owning to the enhanced hydrogen diffusion rate through the multi-phase interface. This work demonstrates the potential of the (La0.33Y0.67)5Ni17.5Mn0.9Al0.6 alloy as high-performance Ni-MH battery anode.

Enhanced electrochemical hydrogen storage properties of Ti49Zr26Ni25 quasicrystal alloy by doping with CO2-activated porous graphene

Ti49Zr26Ni25 quasicrystal alloy was fabricated via mechanical alloying and subsequent annealing. In order to enhance the electrocatalytic activity and conductivity of Ti49Zr26Ni25, the porous graphene (PoRGO) material was synthesized by a facile CO2 activation treatment of reduced graphene oxide (RGO). The composites of Ti49Zr26Ni25 doping with different amount of PoRGO were manufactured through ball milling. During the electrochemical hydrogen storage test, the porous Ti49Zr26Ni25 + PoRGO exhibited higher discharge capacity than Ti49Zr26Ni25 + CRGO and conventional Ti49Zr26Ni25 alloy. Moreover, the additive amount of PoRGO had great influence on the electrochemical properties of Ti49Zr26Ni25. Eventually, 5 wt% PoRGO modified Ti49Zr26Ni25 alloy electrode achieved a highest discharge capacity of 270 mAh/g. The large specific surface area and distinctive porous structure of porous graphene could offer more electrochemical active sites and facilitate the hydrogen diffusion. In the meantime, the cycling stability, high-rate dischargeability (HRD) and kinetic properties of Ti49Zr26Ni25 were also improved after PoRGO loading. Consequently, porous graphene can be potential used as the dopant for the modification of hydrogen storage alloys.

Sonochemical synthesis, characterization and investigation of the electrochemical hydrogen storage properties of Ho3Fe5O12/Mg2Al(OH)7 nanocomposites

It has been noted that hydrogen has attracted extensive consideration in the field of new energy, resulting in a wide range of studies concerning hydrogen production, storage, and use. As part of this research, mixed metal oxide materials with double layer hydroxides are primarily studied for their hydrogen storage capacity. In terms of hydrogen storage capacity, the sonochemically synthesized Ho3Fe5O12/Mg2Al(OH)7 nanocomposites (HF/MgAl(OH)) with different ratios of Ho3Fe5O12 to Mg2Al(OH)7 were compared with pristine LDH of Mg2Al(OH)7. It has been demonstrated that the capacity of Ho3Fe5O12/Mg2Al(OH)7 nanocomposites (422 mAhg−1) with a 1:1 ratio of Ho3Fe5O12 to Mg2Al(OH)7 is significantly higher than pristine LDH (213 mAhg−1).

Synthesis of Ni nanoparticles embedded porous Mo2C nanospheres for enhancing the electrochemical hydrogen storage properties of Co2B material

The porous Mo2C nanospheres were prepared by a high temperature calcination process. Different proportions of Ni nanoparticles were anchored and evenly distributed within the internal structure of porous Mo2C nanospheres via a hydrothermal process. Co2B hydrogen storage material was synthesized by a high temperature solid phase method. The Co2B + Mo2C and Co2B + Ni/Mo2C composites were manufactured via ball milling to improve the electrochemical hydrogen storage properties of Co2B. Eventually, the active materials doped Co2B composites electrodes revealed higher discharge capacities than conventional Co2B. More electrochemical active sites were provided for hydrogen adsorption and charger transfer owing to the extraordinary porous nanostructure and large specific surface area of Mo2C nanospheres. Moreover, the loaded Ni nanoparticles could further promote the electrical conductivity and electrocatalytic activity of Co2B. As a result, the Ni/Mo2C-1 modified Co2B electrode achieved a highest discharge capacity of 688.7 mAh/g. The two active species of porous Mo2C nanospheres and Ni nanoparticles played a synergistic role during the charging/discharging processes. In addition, the high-rate dischargeability (HRD), kinetic properties and corrosion resistance of Co2B were improved with the addition of Mo2C and Ni/Mo2C-1.

Effects of Zr addition on electrochemical characteristics of MgTiMnNi hydrogen storage alloys

The electrochemical hydrogen storage properties of 25 h milled Mg0.80Ti0.175Mn0.025ZrxNi1-x (x = 0, 0.025, 0.05, 0.1) quinary alloys were investigated. The substitution of Zr for Mg or Ni leads to an increase in structural disorder and amorphization. Thus, the maximum discharge capacity and the cycling stability of MgNi-based alloys can be enhanced. The x-ray diffraction patterns indicate that all additive elements are entirely dissolved in the synthesized alloys, and amorphous structure was successfully obtained by 25 h milling. Among the milled alloys, the Mg0.80Ti0.175Mn0.025Zr0.10Ni0.90 alloy exhibited the best discharge capacity of 604 mA h g−1 at the initial charge/discharge cycle. The obtained results demonstrate that using multi-component compositions is beneficial for enhancing the structural and cyclic stability of MgNi-based alloys. Therefore, substituting additive elements for Mg or Ni may offer impressive performance for efficient hydrogen storage applications.

Preparation and hydrogen storage properties of single-phase Ce2Ni7-type La–Sm–Y–Ni based hydrogen storage alloy

LaSm0.4Y1.6Ni10.5Mn0.4Al0.2 hydrogen storage alloy with a Ce2Ni7-type single-phase has been prepared and its electrochemical properties and hydrogen storage properties are systematically investigated. The crystal structure of the alloy transformed completely into the Ce2Ni7-type single-phase via annealing at 1323 K for 16 h. The Ce2Ni7-type single-phase alloy has promising electrochemical properties, including 0.2Cmax = 385.8 mAh/g, 1Cmax = 356.8 mAh/g, and S100 = 86.72%. The HRD of the Ce2Ni7-type single-phase alloy is primarily determined by the charge transfer rate, which is HRD1500 = 75.75% and the corresponding electrochemical capacity at 1500 mA/g is 272.7 mAh/g. The PCT curves of the alloy present double pressure platforms owing to the hydrogen atoms occupying the [A2B4] subunit preferentially and entering the [AB5] subunit subsequently. Similarly, because the lattice expansion rates of the [A2B4] and [AB5] subunits vary discordantly throughout hydrogen absorption/desorption, the hydrogen storage capacity of the alloy experiences irreversible losses.

Preparation of carbon nanofiber supported Co nanoparticles for improving the electrochemical hydrogen storage properties of Co9S8 alloy

Co9S8 alloy was synthesized through mechanical ball milling, and cobalt/carbon nanofiber (Co/CNF) was prepared by the electrospinning process. The addition of Co and CNF increased the discharge capacity of Co9S8 to 563.4 mA/g. Furthermore, the composite electrode exhibited superior high-rate discharge capability, corrosion resistance, and other kinetic properties. CNF provides high conductivity and more reaction sites for Co nanoparticles. Co nanoparticles participate in redox reactions and show a catalytic effect. Moreover, the synergistic effect of CNF and Co also promotes the electrochemical hydrogen storage and kinetic performances of Co9S8 alloy.

Combination of ZIF-67 derived hollow porous Co9S8 nanocages and MWCNTs for electrochemical hydrogen storage applications

By using zeolitic imidazolate framework of ZIF-67 as the precursor, the hollow porous Co9S8 (H–Co9S8) nanocages are synthesized via the sulfidation reaction and thermal treatment processes. The ordinary solid Co9S8 (S–Co9S8) particles are prepared by hydrothermal method. To improve the conductivity and activity of the Co9S8 materials, H–Co9S8 + MWCNTs and S–Co9S8 + MWCNTs composites are fabricated by ball milling. The electrochemical hydrogen storage properties of H–Co9S8 and H–Co9S8 + MWCNTs electrodes are tested via a three-electrode system for the first time. Ultimately, the H–Co9S8 nanocages with hollow porous structure show higher discharge capacity of 667.1 mAh/g than the S–Co9S8 particles. The electrochemical performance enhanced after doping with MWCNTs. H–Co9S8 + MWCNTs displays the highest discharge capacity of 683.5 mAh/g. Additionally, the preferable high-rate dischargeability, corrosion resistance, and improved kinetic properties are also achieved for H–Co9S8 + MWCNTs. H–Co9S8 with a unique hollow structure and large specific surface area can offer sufficient electrochemical active sites to anchor hydrogen, meanwhile, MWCNTs with excellent electrical conductivity can further provide fast channels for charge transfer and improve the electrocatalytic activity of Co9S8 electrode during the charging/discharging processes.

Preparation of TiO2 nanofibers, porous nanotubes, RGO/TiO2 composite by electrospinning and hydrothermal synthesis and their applications in improving the electrochemical hydrogen storage properties of Co2B material

Co2B hydrogen storage material was prepared via a high temperature solid phase process. The TiO2 nanofibers (TiO2–NF) and TiO2 porous nanotubes (TiO2-NT) with different size, structure and morphology were fabricated by electrospinning and hydrothermal synthesis. In order to improve the conductivity, the reduced graphene oxide/TiO2 nanotubes composite (RGO/TiO2-NT) was synthesized by an alkaline hydrothermal process. The three-dimensional porous TiO2 nanotubes were attached to the two-dimensional RGO and formed a uniform dispersion. For the purpose of improving the electrochemical performance of Co2B, composites of Co2B doped with TiO2–NF, TiO2-NT and RGO/TiO2-NT were manufactured by ball milling. Ultimately, all the composite electrodes showed higher discharge capacities than ordinary Co2B. Among them, Co2B modified with RGO/TiO2-NT exhibited the highest discharge capacity (691.4 mAh/g). TiO2-NT with large specific surface area and unique tubular porous structure can offer sufficient electrochemical active sites to anchor hydrogen and improve the electrocatalytic activity of Co2B, meanwhile, the RGO component in RGO/TiO2-NT with excellent electrical conduction can further provide fast channels for charger transfer during the charging/discharging processes. Moreover, the corrosion resistance, HRD and kinetics performance of Co2B were also enhanced after doping of TiO2–NF, TiO2-NT and RGO/TiO2-NT.

Electrochemical study of the LaFe0.8Ni0.2O3 perovskite-type oxide used as anode in nickel-metal hydride batteries

The electrochemical hydrogen storage properties of the LaFe0.8Ni0.2O3 perovskite-type oxide used as the negative electrode in the nickel metal-hydride battery have been studied in this work. This oxide has been synthesized by the sol-gel method and its structure and electrochemical properties are systematically studied. X-ray diffraction (XRD) analysis showed that the LaFe0.8Ni0.2O3 perovskite-type oxide consists of a single phase and crystallizes in the orthorhombic space group with the Pnma space group. The electrochemical cycling properties of the LaFe0.8Ni0.2O3 negative electrode were carried out at 25 °C using the galvanostatic charging and discharging polarization method for 50 cycles. An optimization of the experimental parameters were carried out in order to optimize the charging potential, the charging and discharging current and the charging time. The best properties were observed for the optimal parameters, such as a discharge potential of 0.4V, a charge and discharge current of 4.44 mA g−1 and a charge time of 5 h.

Synthesis of ZIF-8 derived porous carbon/NiS hexahedral composite and its application in improving the electrochemical hydrogen storage properties of Co–P material

Thermal treatment of zinc-based MOF (ZIF-8) is conducted to prepare ZIF-8 derived porous carbon (ZIF-8-C). ZIF-8-C/NiS hexahedral composites with different C/Ni mole ratios (C@NiS-2, C@NiS-4 and C@NiS-6) are synthesized by solvothermal method. Co–P hydrogen storage material is prepared via mechanical alloying. Then, composites of Co–P coated with NiS, ZIF-8-C and C@NiS are obtained by ball-milling. Eventually, C@NiS-4 coated Co–P electrode exhibits higher discharge capacity of 624.8 mAh/g than separate NiS or ZIF-8-C modified Co–P and original Co–P electrodes. The HRD, corrosion resistance and kinetics properties of Co–P are also improved after C@NiS-4 loading. The enhanced kinetics performance and electrochemical activities of Co–P + C@NiS-4 may be due to the synergistic effect between flexible porous carbon ZIF-8-C and active NiS nanosheets, which can further accelerate the hydrogen diffusion during the charging/discharging processes.

Improving hydrogen-induced crystallization and electrochemical hydrogen storage properties of MgNi amorphous alloy with CoB addition

Amorphous MgNi-based alloy demonstrates the potential to be a candidate for Ni-MH battery anode materials due to its low cost and high capacity. However, the poor cyclic performance limits its practical application, which was predominantly attributed to the electrochemical oxidization of Mg in alkaline electrolytes. In this work, the amorphous CoB was added to successfully enhance the structural stability and cyclic performance of the amorphous MgNi alloy electrode. For the milled MgNi mixture containing 5 wt% CoB, the capacity maintains 174.8 ± 7.6 mAh/g after 30 cycles, increasing ∼114.6 mAh/g than pure MgNi. DSC and TG results indicate that the CoB addition can greatly increase the crystallization temperature of amorphous MgNi, implying higher resistance to hydrogen-induced crystallization in the charge/discharge cycles of MgNi amorphous alloy electrodes. As a result, the amorphous composite structure could effectively improve the electrochemical performances of amorphous MgNi alloys.