Ni Battery Research Articles

Synergistic effect of ZnO@Bi/C sphere for rechargeable Zn[sbnd]Ni battery with high specific capacity

ZnO@Bi/C sphere with a distinctive core-shell construct is designed and fabricated by using solvothermal method, which is applied as a novel electrode material of ZnNi battery for the first time. The analytical results manifest that the core of the ZnO@Bi/C sphere coated with carbon layer consists of a large number of ZnO nanoparticles (NPs), and in situ modified metal Bi is embedded in the amorphous carbon layer and ZnO NP core uniformly, thereby forming a unique core-shell construct. Unlike pure ZnO anode, the ZnO@Bi/C sphere shows more remarkable specific capacity and cycling stability: that is, after cycling 180 times at 1 C, the discharge specific capacity remains at 630.7 mAh g−1. The excellent electrochemical properties are attributed to the synergistic effect of carbon and metal Bi in the ZnO@Bi/C sphere, which is conducive to decreasing the voltage polarization and promoting the battery reversibility.

Enhanced electrochemical properties of LaFeO3 with Ni modification for MH–Ni batteries

In this work, we synthesized LaFeO3–xwt%Ni (x = 0, 5, 10, 15) composites via a solid-state reaction method by adding Ni to the reactants, La2O3 and Fe2O3. Field-emission scanning electron microscopy (FE-SEM) and energy-dispersive X-ray spectroscopy (EDS) results revealed that Ni powders evenly dispersed among the LaFeO3 particles and apparently reduced their aggregation, which imparted the composites with a loose structure. Moreover, the Ni formed a conductive network, thus improving the conductivity of the composites. The maximum discharge capacity of the LaFeO3 electrodes remarkably increased from 266.8 mAh·g–1 (x = 0) to 339.7 mAh·g–1 (x = 10). In particular, the high-rate dischargeability of the LaFeO3–10wt%Ni electrode at a discharge current density of 1500 mA·g−1 reached 54.6%, which was approximately 1.5 times higher than that of the pure LaFeO3. Such a Ni-modified loose structure not only increased the charge transfer rate on the surface of the LaFeO3 particles but also enhanced the hydrogen diffusion rate in the bulk LaFeO3.

Communication—Bi@CMC Composite as a Multifunctional Electrolyte Channel for the Anode of Rechargeable Zn–Ni Battery

A composite of bismuth and carboxymethyl cellulose (Bi@CMC) was successfully prepared and used as an additive in rechargeable Zn–Ni battery. The Bi@CMC composite combines the characters of electric conduction, hydrogen evolution reaction (HER) suppression and hydrophilicity, since hydrophilic carboxymethyl cellulose (CMC) fibers are coated by high-HER overpotential Bi particles. A Zn–Ni battery using an anode containing Bi@CMC demonstrated a higher coulombic efficiency and discharge capacity than pristine CMC. In addition, the rationality of the method which utilized the KOH/Zn(OH)42− electrolyte to alkaline rechargeable zinc-based batteries is discussed.

Polydopamine-coated nano-ZnO for high-performance rechargeable Zn–Ni battery

A polydopamine (PDA)-coated nanosized ZnO is prepared and employed as an anode material of Zn–Ni battery for the first time. The battery, which used the PDA-coated ZnO, displays a high specific capacity of 364.3mAhg−1 at 1 C after 200 cycles, which is significantly stable than that of the original ZnO. The highly hydrophilic PDA layers serve as ionic transfer channels and can provide the diffusion of OH− into the inner electrode. These layers can also decrease polarization voltage and improve cycling performance. Meanwhile, a flexible and tense PDA film can retain the completeness of zinc electrode and prevent shape change. Moreover, the current distribution and zinc deposition on the surface of the electrode becomes uniform as the PDA coats the single ZnO particles.

In situ neutron powder diffraction study of phase-structural transformations in the La–Mg–Ni battery anode alloy

This work was focused on studies of temperature-induced phase-structural transformations in the as-cast La2MgNi9 metal hydride battery electrode alloy. The interactions in the alloy were studied by in situ neutron powder diffraction at temperatures ranging from 300 K to 1273 K. Initial alloy is multi-phase structured, containing six different intermetallics with five stoichiometric compositions. These include the targeted rhombohedral La2MgNi9 as the main phase constituent, together with three electrochemically active intermetallics, La3MgNi14 (3R), La4MgNi19 (2H) and La4MgNi19 (3R). Furthermore, the alloy contained two “ballast” intermetallics, LaNi5 and LaMgNi4. Various transformations take place on heating, leading to the significant changes in the contents of the constituent intermetallics, first of all to the disappearance of LaNi5 and LaMgNi4. Thermal volume expansions of the studied intermetallics were well fitted by the linear dependences and resulted in similar values of 4.3–5.5 vol.% at 1223 K as compared to 300 K.

The effect of carbon-polyaniline hybrid coating on high-temperature electrochemical performance of perovskite-type oxide LaFeO3 for MH-Ni batteries.

An efficient carbon-polyaniline (PANI)-coated method was applied for perovskite-type oxide LaFeO3 to enhance its high-temperature electrochemical performance. Transmission electron microscopy (TEM) results reveal that LaFeO3 particles are evenly coated with carbon and PANI hybrid layers after carbon-PANI treatment. The carbon layers prevent the nanosized LaFeO3 particles from aggregation and allow the electrolyte to penetrate in every direction inside the particles. The PANI layers also enhance the electrocatalytic activity, facilitating hydrogen protons transferring from the electrolyte to the electrode interface. The cooperation of carbon and PANI hybrid layers results in a significant enhancement of the electrochemical performance at high temperatures. At an elevated temperature (60 °C), the maximum discharge capacity of the LaFeO3 electrodes remarkably increases from 231 mA h g(-1) to 402 mA h g(-1) and the high rate dischargeability at a discharge current density of 1500 mA g(-1) (HRD1500) increases from 22.7% to 44.3%. Moreover, the hybrid layers mitigate the corrosion of LaFeO3 electrodes by reducing the loss of active materials in the alkaline electrolyte, leading to increase in the capacity retention rate from 67.1% to 77.6% after 100 cycles (S100).

Thermodynamic properties of vitreous electrodes in a Ni/NiP glass-crystal Galvanic cell

In the present paper, we present and discuss data on the thermodynamic properties of electrochemically deposited crystalline and vitreous metallic electrodes, focusing our attention on the model system of vitreous Ni/P alloys. Galvanic cells based on the glass→crystal transition are constructed and their electrochemical properties are analyzed as an alternative approach for the complete thermodynamic description of amorphous electron conductors. The EMF of the glass→crystal Ni/P–Ni battery when both crystalline Ni and the amorphous Ni/P layers electrodes placed in their native solution, gives ΔE(T) values from 0.120 to 0.140V in the temperature range from 293 to 333K. For the same system, we report a corrosion potential difference of ΔE=0.100V (at 298K, in a 1M H2SO4 electrolyte) between the glassy and the crystalline electrodes. The kinetic considerations of the deposition process provide a new way for interpretation of the mechanism of formation of amorphous deposits during electrodeposition and electroless formation of amorphous Ni3P layers based on a kinetic interpretation of Ostwald's Rule of Stages.

Size effect investigation on battery performance: Comparison between micro- and nano-particles of β-Ni(OH) 2 as nickel battery cathode material

In this work we report on the comparison between nano- and micro-particles of β-Ni(OH) 2 as cathode material of Ni battery. The synthesis of nano- and micro-particles of nickel hydroxide is done by two different procedures: sonication process and stirrer. Nano-particles of β-Ni(OH) 2 are synthesized by chemical precipitation from a solution containing NiCl 2·6H 2O and surfactant under ultrasonic irradiation. Micro-particles of β-Ni(OH) 2 are synthesized by a similar procedure while applying magnetic stirring instead of ultrasonic. The products are characterized by scanning electron microscopy and X-ray powder diffraction. Under the optimized conditions nickel hydroxide nano-particles, with an average particle size of 18 nm, are obtained. Cyclic voltammetric (CV) studies show a pair of well-defined peaks for Ni(OH) 2/NiOOH redox reaction, along with faster proton diffusion coefficient and higher oxygen evolution potential for nano-particles of nickel hydroxide compared to that of micro-particles. Electrochemical impedance spectroscopy (EIS) studies of Ni(OH) 2 electrodes show that the reaction occurring at the nickel hydroxide is controlled by charge transfer and Warburg diffusion. The β-Ni(OH) 2 nano-particles are found to exhibit a superior cycling reversibility and improved capacity when they are used as positive electrode materials of alkaline rechargeable batteries.

Effects of additions on AB5-type hydrogen storage alloy in MH–Ni battery application

Abstract The AB5-type hydrogen storage alloy of Mm0.3Ml0.7Ni3.55Co0.75Mn0.4Al0.3 were synthesized and mixed with PVA (Polyvinyl Alcohol) or different percentage Ni powder as the test samples. The cycle stabilities of the composites were tested in 6 M KOH electrolyte through electrochemical method. The results indicated that all the samples with Ni powder have better cycle stabilities and flatter discharge voltage platform. The sample of Mm0.3Ml0.7Ni3.55Co0.75Mn0.4Al0.3 + 200 wt.% Ni has the highest capacity conservation rate of 80.5% and the longest discharge time of 5.2 h. The SEM images show that the particle diameters of the alloy decreased by 2 μm and the surface smoothed without sharp edges after adding Ni powder. It can be presumed that adding Ni can improve the cycle stability of the alloy of Mm0.3Ml0.7Ni3.55Co0.75Mn0.4Al0.3 in the alkaline electrolyte and enhance the reaction rate in the charge/discharge cycles.

Preparation of alkaline solid polymer electrolyte based on PVA–TiO 2–KOH–H 2O and its performance in Zn–Ni battery

A novel composite alkaline polymer electrolyte based on poly(vinyl alcohol) (PVA) polymer matrix, titanium dioxide (TiO 2) ceramic fillers, KOH, and H 2O was prepared by a solution casting method. The properties of PVA–TiO 2–KOH alkaline polymer electrolyte films were studied by X-ray diffraction (XRD), differential scanning calorimetry (DSC), scanning electron microscopy (SEM), and AC impedance techniques. DSC and XRD results showed that the domain of amorphous region in the PVA polymer matrix augmented when TiO 2 filler was added. The SEM result showed that TiO 2 particles dispersed into the PVA matrix although some TiO 2 aggregates of several micrometers were formed. The alkaline polymer electrolyte showed excellent electrochemical properties. The room temperature (20 °C) ionic conductivity values of typical samples were between 0.102 and 0.171 S cm −1. The Zn–Ni secondary battery with the alkaline polymer electrolyte PVA–TiO 2–KOH had excellent electrochemical property at the low charge–discharge rate.

Structure and electrochemical properties of Ti 0.25V 0.35Cr 0.40− xNi x ( x=0.05–0.40) solid solution alloys

The structure and electrochemical properties of Ti 0.25 V 0.35 Cr 0.40−x Ni x (x=0.05 –0.40) solid solution alloys have been studied in the paper. It is found that these alloys consist of a main solid solution phase with body centered cubic (bcc) structure and a little TiNi-based secondary phase. The solid solution alloys show easier activation behavior at 313 K as a negative electrode material for MH–Ni battery. With changing x from 0.05 to 0.30, the discharge capacity and the high-rate dischargeability increase. The discharge capacity increases with increasing temperature. The maximum discharge capacity is 240 mA h / g at 313 K for x=0.30 and 280 mA h / g at 343 K for x=0.15.

Self-discharge of Fe–Ni alkaline batteries

The effect of FeS and PbS on capacity and self-discharge of an iron porous electrode used in a Fe–Ni battery was investigated. Addition of 1 wt.% FeS or 1 wt.% PbS promotes a significant increase in capacity and inhibits the self-discharge of the iron electrode. This effect is most significant in the presence of PbS.

Effects of Cycling Conditions of Active Material from Discharged Ni Positive Plates Studied by Inelastic Neutron Scattering Spectroscopy

A series of cycled Ni battery plate materials has been examined by means of inelastic neutron scattering spectroscopy in order to determine the nature of the protons in the discharged and cycled material. Our results clearly demonstrate that some amount of the NiOOH phases which form on oxidation does not convert back to upon discharging the battery and that this amount increases with the number of cycles the battery undergoes. Moreover, we have identified vibrational signatures of lattice water and found that its amount increases with KOH concentration used in the cell. Since cells operated at higher KOH concentrations are known to fail after fewer cycles, our inelastic neutron scattering studies clearly implicate the irreversible formation of lattice water as one of the main reasons for this failure.