Alkaline Secondary Batteries Research Articles

Synthesis and electrochemical performance of mixed phase α/β nickel hydroxide by codoping with Ca2+ and PO4 3−

Nickel hydroxide with a unique mixed phase α/β-Ni(OH)2 was prepared by partially substituting Ca2+ for Ni2+ with supersonic co-precipitating method firstly. The crystal structure and morphology of the samples were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), and scanning electron microscopy (SEM). The results show that the Ca-substituted Ni(OH)2 by adding PO4 3− is α/β mixed phase, while the undoped Ni(OH)2 and the Ca-substituted Ni(OH)2 without adding PO4 3− are pure β phase. Furthermore, the Ca-substituted Ni(OH)2 by adding PO4 3− exhibits irregular shape and contains many intercalated water molecules and anions as proven by SEM and FT-IR. Meanwhile, the prepared samples were added into micro-sized beta nickel hydroxide to form biphase electrode materials for Ni-MH battery. The electrochemical performances of the biphase electrodes were characterized by cyclic voltammetry (CV) and charge/discharge tests. The results demonstrate that the biphase electrode with mixed phase α/β-Ni(OH)2 exhibits higher electrochemical activity, better electrochemical reversibility and charge efficient, higher discharge potential, and better cyclic stability. The specific discharge capacity of Ca-substituted α/β-Ni(OH)2 electrode can retain 271.7 and 238 mAh/g after 80 cycles at 0.2 and 0.5 C, respectively. This indicates that it may be a promising positive active material for alkaline secondary batteries. The results reported in this work may be useful for the designing and synthesizing of nickel hydroxide materials with superior performance.

Influence of annealing temperature on the structure and electrochemical performance of the Fe3O4 anode material for alkaline secondary batteries

High-performance Fe3O4 polyhedrons as alkaline secondary battery anode materials have successfully been synthesized using a facile co-precipitation method with a subsequent annealing treatment at 700°C for 1h. The physical and electrochemical properties of the Fe3O4 samples annealed at different temperatures are investigated. It has been discovered that the annealing temperature plays a vital role in improving the physical and electrochemical performances of the Fe3O4 materials. The results also indicate that the Fe3O4 sample annealed at 700°C performs better (faster activation rate, higher specific discharge capacity, better high-rate ability and cycle stability) than the samples annealed at other temperatures. The specific discharge capacity of the 700°C-annealed Fe3O4 reaches 604.2mAh g-1 at a current density of 120mA g-1 with a charging efficiency of 83.9%. Moreover, discharge capacities of 587.6, 539.5 and 500.1 mAh g-1 are achieved at 240, 600 and 1200mA g-1, respectively, exhibiting remarkable high-rate discharge capability. This performance improvement may be attributable to better reaction reversibility, lower charge transfer impedance and better inhibiting effect on hydrogen evolution reaction of the material. We believe that this Fe3O4 polyhedron is a promising candidate as the anode material for high-performance alkaline secondary batteries.

Hydrothermal synthesis of ultrathin hexagonal nickel hydroxide nanosheets

Nickel hydroxide, Ni(OH)2 is widely used in electrodes of nickel-based alkaline secondary batteries. Ultrathin hexagonal Ni(OH)2 nanosheets of space group P-3m1 were hydrothermally prepared at 200°C for 10h. Their diameter and thickness were 200–300 and 3–5nm, respectively. Their formation was attributed to the oriented assembly of growing particles, which was assisted by surfactant molecules. The specific surface area of the Ni(OH)2 nanosheets was 8.66m2/g. Their magnetization curve exhibited linear paramagnetic behavior across the entire measurement region.

Recent advances in energy storage and conversion systems based on layered double hydroxides materials

Recently, considerable efforts have been devoted to exploiting clean and efficient power sources owing to the increasing demands for low-cost and renewable energy, coupled with concerns over environmental pollution. Layered double hydroxides (LDHs) are a class of 2D anionic clays which have been widely used in the fields of electrochemical sensors, supercapacitors, alkaline secondary batteries and fuel cells, due to their desirable properties including low cost, high electrochemical activity and stability. In this review, we summarized the recent progress in the controlled fabrication of electrochemically active LDHs materials and their employment in energy storage and conversion. Furthermore, current challenges and future strategies are discussed from the viewpoint of material design and practical application.

Alternating assembly of Ni–Al layered double hydroxide and graphene for high-rate alkaline battery cathode

We report a Ni-Al layered double hydroxide (LDH)-graphene superlattice composite via alternating assembly of the exfoliated thin flakes with opposite charges that show stable high-rate performance for alkaline battery cathodes.

A one-pot method to prepare a ZnO/Ag/polypyrrole composite for zinc alkaline secondary batteries

A ZnO/Ag/polypyrrole (ZAP) composite was synthesized by a facile one-pot method in which silver ammonia complex ions were reduced to metallic silver using a pyrrole monomer as the reducing agent. Meanwhile, the pyrrole monomer was oxidized and formed polypyrrole.

Electrochemical properties of ZnO added with Zn-Al-hydrotalcites as anode materials for Zinc/Nickel alkaline secondary batteries

Zn-Al layer double hydroxides (LDHs) were prepared through a simple hydrothermal method and proposed as an anode additive for Zn/Ni alkaline secondary batteries. The X-ray diffraction (XRD) and scanning electron microscopy (SEM) of sample LDHs indicates that LDHs was well prepared. The electrochemical properties of the ZnO anodes with different contents of Zn-Al-LDHs were investigated by galvanostatic charge-discharge, cyclic voltammetry (CV) and electrochemical impedance spectroscope (EIS). The structures and morphologies after cycles were also measured by SEM. The results indicate that the presence of Zn-Al-LDHs in the electrode exhibits better electrochemical performance compared with the pure ZnO electrode, such as superior electrochemical cycle stability, better reversibility and higher discharge capacity and utilization ratio. Especially for the electrode added with 24% Zn-Al-LDHs, the discharge capacity hardly declined over 250 cycles, the average utilization ratio could reach 98.5%, and the electrode had no obvious shape change and Zn dendrites after the cycling tests.

Effect of the length and surface area on electrochemical performance of cobalt oxide nanowires for alkaline secondary battery application

One-dimensional porous Co3O4 nanowires with different length have been successfully synthesized by thermal decomposition of Co-NA polymer precursors at various hydrothermal reaction times. The positive effects of longer nanowires and larger surface area on electrochemical performance of Co3O4 samples were investigated systematically. All the as-prepared Co3O4 samples display excellent discharge capacities and cycle stability on account of large surface area and porous structure, indicating great potential application of porous Co3O4 nanowires for alkaline rechargeable batteries. The Co3O4-24 h sample with the longest length shows the most outstanding electrochemical performance, and displays the maximum discharge capacity of 450.1 mAh g−1 with the capacity retention of 90.4% after 100 cycles at a current density of 100 mA g−1. Electrochemical reactions between Co and Co(OH)2 occurring on the Co3O4 electrodes are investigated by XRD, cyclic voltammetry (CV) and charge–discharge measurements.

Synthesis of cobalt oxide-reduced graphene nanocomposite and its enhanced electrochemical properties as negative material for alkaline secondary battery

A potential negative electrode material Co3O4@rGO is synthesized via a facile reflux condensation route. The electrochemical performances of Co3O4@rGO composite for alkaline rechargeable Ni/Co batteries have been systemically investigated for the first time. The reduced-graphene can remarkably enhance the electrochemical activity of Co3O4 materials, leading to a notable improvement of discharge capacity, cycle stability and rate capability. Interestingly, the maximum discharge capacity of Co3O4@rGO-20 (additive amount of GO is 20 mg) electrode can reach 511.4 mAh g−1 with the capacity retention of 89.1% after 100 cycles at a discharge current of 100 mA g−1. A properly electrochemical reaction mechanism of Co3O4@rGO electrode is also constructed in detail.

Influences of Structural Differences of Layered Double Hydroxides on Their Hydroxide Ion Conductivities

Anion-exchange membrane fuel cells (AEMFCs) have attracted much attention since they can potentially overcome the stumbling blocks of proton-exchange membrane fuel cells. There are many research approaches to improve the performance of AEMFCs, and one of them is to seek new ion conductors that effectively transport hydroxide ions at the ambient temperature. Ion conductors with not only high ion conductivities but also high robustness are strongly required to realize the high-efficiency and long-life performance of AEMFCs. Among such ion conductors, we have focused on layered double hydroxides (LDHs). The basic layer structure of LDHs is based on that of brucite [Mg(OH)2]. In the brucite lattice, magnesium ions are surrounded octahedrally with hydroxide ions, and these octahedral units form infinite plane of the 2D layers. LDHs are derived by the substitution of a fraction of divalent cations in brucite by trivalent cations, which lead to positive charges in hydroxide layers. These charges are balanced by intercalation of anions and water between the positively charged layers. The possibility of varying the kinds and relative proportions of the di- and trivalent cations as well as the interlayer anions gives rise to the large variety of LDHs with a general formula [M2+ 1−xM3+ x(OH)2]x+[An−]x/n·yH2O, where M2+ and M3+ are di- and trivalent metal cations respectively, and An− is an anion. This flexibility in composition of LDHs has induced an increase in interest for many applications, such as catalyst supports, ion-exchange and adsorption, drug-delivery system, etc. In addition, some research groups including our group recently reported that LDHs operated as an OH−conductor, which could be applied for alkaline fuel cells, metal-air secondary batteries, and alkaline secondary batteries. In this study, we focus on the nature of ion conductivities in LDHs. To understand the mechanism of ion conductivities in LDHs in detailed, we synthesized Mg-Al and Mg-Ga LDHs with different relative proportions of di- and trivalent metal cations, and evaluated the influence of the proportion of trivalent cation on their ion conductivities by electrochemical measurements. We chose Mg-Al and Mg-Ga LDHs since they are widely used in LDH studies. We shed light on the structural relationship, which could guide the design of improved or novel hydroxide-conductive materials. Using the co-precipitated method, we successfully synthesized Mg-Al-CO3 and Mg-Ga-CO3 LDHs with various proportions of trivalent cations. In the results of X-ray diffraction, as the Mg/Al ratio decreased from 4 to 2, the 003 diffraction peak positively shifted, which indicates that layer height between metal hydroxide layers were diminished. This decrease in the layer height was due to an increase in electrostatic attraction between positive and negative layers. In contrast, resulted LDHs were characterized in similar BET surface areas and mean diameter in spite of changing the proportion of trivalent cations. Both series of LDHs did not displayed a linear increase in ion conductivities as a function of the proportion of trivalent cations, but a sharp raise appeared only for Mg2+/Al3+ = 2 and Mg2+/Ga3+ = 3. Based on the results of electron-diffraction analysis, Mg-Al and Mg-Ga LDHs, showing the highest ion conductivities had the ordered honeycomb cation arrangement within some parts of (0001) hydroxide layers. Other LDHs had complete random cation distribution. The ordered honeycomb structure was a cation distribution that can elude direct contact of M3+−M3+ and diminish the distance of the nearest trivalent cations; “neither near nor far” for individual interlayer anions. These things for the ordered cation arrangements not only demonstrate a helpful strategy for improving ion conductivities of LDHs, but also present new insights into structural relationship between immobile cationic charge centers and mobile interlayer anions.

Development of flexible secondary alkaline battery with carbon nanotube enhanced electrodes

We present the development of flexible secondary alkaline battery with rechargeability similar to that of conventional secondary alkaline batteries. Multiwalled carbon nanotubes (MWCNTs) were added to both electrodes to reduce internal resistance, and a cathode containing carbon black and purified MWCNTs was found to be most effective. A polyvinyl alcohol–poly (acrylic acid) copolymer separator served the dual functions of electrolyte storage and enhancing flexibility. Additives to the anode and cathode were effective in reducing capacity fades and improving rechargeability.

Ball-milled Ni-Mn-Zn hydroxide for alkaline secondary battery

In our previous study, Mn-substituted nickel hydroxide (Ni0.8Mn0.2(OH)2) was prepared by a simple ball milling method to reduce the cost of nickel hydroxide for alkaline secondary battery, but compared to the Ni(OH)2 electrode, the Ni0.8Mn0.2(OH)2 one showed an obvious decrease in its discharge potential. In this paper, Zn and Mn co-substituted nickel hydroxide (Ni0.8Mn0.2 − x Zn x (OH)2, x = 0–0.075) is prepared by ball milling. The results of the cyclic voltammetry (CV) tests illustrate that the co-reduction of Mn(IV) to Mn(III) and NiOOH is observed on the Ni0.8Mn0.2 − x Zn x (OH)2 electrodes, and it has a lower reduction potential than NiOOH. The co-substitution of Zn can effectively increase the co-reduction potential. The ball-milled Ni0.8Mn0.15Zn0.05(OH)2 electrode has a similar capacity (about 270 mAh g−1 at a 0.2C rate) and cycling durability to the commercial Ni(OH)2 with ball milling treatment, but the former has better high-power performance.

Zinc Nucleation and Growth in Secondary Alkaline Batteries

Zinc morphology strongly affects the performance of secondary alkaline batteries. The formation of mossy and dendritic structures is detrimental to anode performance and cycle life. The initial stages of zinc deposition on carbon structures are investigated using scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HRTEM) and electron-diffraction. Mossy zinc is formed by the aggregation of zinc clusters in a nucleation-controlled process. Dendritic zinc is formed by the unstable growth of zinc along preferred growth axes. An attempt is made to develop a free-energy based phase-field model of electrodeposition to simulate dendritic growth. Preliminary results using a solidification model are able to qualitatively simulate zinc deposition. Understanding the nucleation and growth processes is key to developing innovations to improve battery performance in alkaline zinc anodes.

Metal Borides As High Capacity Anode Materials for Alkaline Secondary Batteries

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Effect of Novel Substrates on Zinc Anode - Secondary Alkaline Battery Performance

Zinc electrodeposition in alkaline battery has important effect on the performance of the battery and the substrate metal has a strong effect on the performance of zinc anodes, especially at the earliest stages. Rotating disk electrodes were fabricated using 99.9%+ pure metal rods to investigate the performance of zinc deposition on silver, bismuth, copper, iron, nickel and tin substrates. The amount of charge passed in all the experiments was 5 C/cm2. Iron and nickel do not have desirable performance, due to hydrogen evolution. The hydrogen evolution on iron is rapid and soon covers the entire surface of the electrode. Bismuth and tin have desirable performance. The coulombic efficiency on each of these substrates is well in excess of 90% when deposited at -20 mA/cm2. Due to their relatively low cost, tin and bismuth are seen as promising choices of substrate metals in zinc anodes.The morphology of zinc deposition and crystal orientation on copper, nickel and tin substrates was investigated. Zinc deposition is more compact on Sn than on Ni and Cu for the same amount of charge passed. Additionally, Ni and Cu have a propensity to evolve mossy zinc much more easily.The extent of preferred orientation decreases with zinc deposition, and mossy zinc is depositied with almost no texture. Compact zinc has preferred orientation, strongest on Sn.Zinc-based rechargeable batteries are attractive electrical energy storage systems due to their low cost, high energy density and low toxicity. However, zinc redistribution on periodic cycling and dendrite formation is known to severely limit battery life. Short cycle life due to internal short circuits have prevented wide spread secondary storage applications.Zinc electrodeposition in alkaline battery has important effect on the performance of the battery and the substrate metal has a strong effect on the performance of zinc anodes, especially at the earliest stages. Rotating disk electrodes were fabricated using 99.9%+ pure metal rods to investigate the performance of zinc deposition on silver, bismuth, copper, iron, nickel and tin substrates. The amount of charge passed in all the experiments was 5 C/cm2. Iron and nickel do not have desirable performance, due to hydrogen evolution. The hydrogen evolution on iron is rapid and soon covers the entire surface of the electrode. Bismuth and tin have desirable performance. The coulombic efficiency on each of these substrates is well in excess of 90% when deposited at -20 mA/cm2. Due to their relatively low cost, tin and bismuth are seen as promising choices of substrate metals in zinc anodes.The morphology of zinc deposition and crystal orientation on copper, nickel and tin substrates was investigated. Zinc deposition is more compact on Sn than on Ni and Cu for the same amount of charge passed. Additionally, Ni and Cu have a propensity to evolve mossy zinc much more easily.The extent of preferred orientation decreases with zinc deposition, and mossy zinc is depositied with almost no texture. Compact zinc has preferred orientation, strongest on Sn.

In Situ Preparation of 1D Co@C Composite Nanorods as Negative Materials for Alkaline Secondary Batteries

Cobalt-based coordination compounds were successfully prepared via employing nitrilotriacetic acid (NTA) as a complexing agent through a mild surfactant-free solvothermal process. Cobalt ions are linked with the amino group or carboxyl groups of NTA to become one-dimensional nanorods that can be proved by Fourier transform infrared measurement findings. The morphologies of the precursor Co-NTA highly depend on the solvent composition, the reaction time and temperature. The probable growth mechanism has been proposed. After heat treatment, the Co-NTA precursor can be completely converted into Co@C nanorods assembled by numerous core-shell-like Co@C nanoparticles, which preserved the rodlike morphology. The as-prepared Co@C composites display a rodlike morphology with 4 μm length and 100 nm diameter. The electrochemical performances of this novel Co@C material as the alkaline secondary Ni/Co battery negative electrode have been systematically researched. The discharge capacity of the Co@C-1 composite electrode can attain 609 mAh g(-1) and retains about 383.3 mAh g(-1) after 120 cycles (the discharge current density of 500 mA g(-1)). The novel material exhibits a high discharge capacity of 610 and 470 mAh g(-1) at discharge currents of 100 and 1000 mA g(-1), respectively. This suggests that approximately 77% of the discharge capacity is kept when the discharge current density is increased to 1000 mA g(-1) (10 times the initial current density of 100 mA g(-1)). The excellent electrochemical properties could be ascribed to the porous channels of the novel Co@C materials, which is beneficial to electrolyte diffusion and electrons and ions transportation.

The fabrication of a bifunctional oxygen electrode without carbon components for alkaline secondary batteries

The fabrication of a gas diffusion electrode (GDE) without carbon components is described. It is therefore suitable for use as a bifunctional oxygen electrode in alkaline secondary batteries. The electrode is fabricated in two stages (a) the formation of a PTFE-bonded nickel powder layer on a nickel foam substrate and (b) the deposition of a NiCo2O4 spinel electrocatalyst layer by dip coating in a nitrate solution and thermal decomposition. The influence of modifications to the procedure on the performance of the GDEs in 8 M NaOH at 333 K is described. The GDEs can support current densities up to 100 mA cm−2 with state-of-the-art overpotentials for both oxygen evolution and oxygen reduction. Stable performance during >50 successive, 1 h oxygen reduction/evolution cycles at a current density of 50 mA cm−2 has been achieved.

Pd capped MgxTi1−x films: Promising anode materials for alkaline secondary batteries with superior discharge capacities and cyclic stabilities

Pd capped MgxTi1−x films have been prepared by magnetron sputtering, and their electrochemical hydrogen storage properties have been investigated. Results show that the Mg0.85Ti0.15 and Mg0.72Ti0.28 samples exhibit the most promising electrochemical properties, including short activation period, large discharge capacities, excellent cyclic stabilities and superior anti-corrosion behaviors. The maximum capacity of Mg0.85Ti0.15 film is achieved to ∼1100 mAh g−1 after 30 cycles, 80% of which (∼810 mAh g−1) can be maintained even after 150 cycles. Such excellent properties make Pd capped MgxTi1−x films competitive candidates as anode materials of alkaline secondary batteries.

A novel bifunctional oxygen GDE for alkaline secondary batteries

This paper describes a novel procedure for the fabrication of a gas diffusion electrode (GDE) suitable for use as a bifunctional oxygen electrode in alkaline secondary batteries. The electrode is fabricated by pre-forming a PTFE-bonded nickel powder layer on a nickel foam substrate followed by deposition of NiCo2O4 spinel electrocatalyst by dip coating in a nitrate solution and thermal decomposition. The carbon-free composition avoids concerns over carbon corrosion at the potentials for oxygen evolution. The electrode shows acceptable overpotentials for both oxygen evolution and oxygen reduction at current densities up to 100mAcm−2. Stable performance during >100 successive, 1h oxygen reduction/evolution cycles at a current density of 20mAcm−2 in 8M NaOH at 333K was achieved.

Enhanced electrochemical properties of Co/CMK-3 composite as negative material for alkaline secondary battery

Co/CMK-3 composites are synthesized via a facile hydrothermal route. The electrochemical performances of Co/CMK-3 composite as the negative electrode material for alkaline rechargeable Ni/Co batteries have been systemically investigated. Electrochemical measurements show that the CMK-3 can remarkably enhance the electrochemical activity of Co, leading to a notable improvement of the discharge capacity, cycle stability and rate capability. Interestingly, the discharge capacity of Co/CMK-3 (25 mg CMK-3) electrode can reach 519.3 mAh g−1 and retains about 365.8 mAh g−1 after 100 cycles at discharge current of 100 mA g−1. The electrochemical reaction mechanism of Co/CMK-3 composite electrode can be attributed to the electrochemical redox reaction between Co and Co(OH)2.