Electrolytic Manganese Dioxide Research Articles

Interconnected Ni Nanowire Scaffolds for Fast-Charging 3D Thin-Film Lithium-Ion Batteries

The growing market of small consumer electronics, such as cell phones, smartwatches or electronic eyewear requires development of small power sources that allow for both satisfactory usage time and fast charging. Lithium-ion batteries (LIBs) are currently the systems of choice thanks to their high energy and power density. However, downscalling these batteries for small device applications still possess a big challenge. Due to electronically and ionically resistive nature of the active materials, mini-LIBs are currently made only in thin film technology, thus the total output energy and power density are still far too low for consumer device applications. Also, the manufacturing of thin film batteries requires sophisticated PVD/CVD deposition techniques. To overcome these issues, 3D architecturing of the current collector can be employed [1, 2]. This can provide a system where very thin active materials are stacked over enormously large surface area of a 3D current collector to yield a cell with both high power density (due to reduced materials thickness) and high energy density (thanks to large total volume of the active materials). Herein, we report reproducible fabrication of 3D-interconnected nickel nanowires (Fig. 1) prepared by electrodeposition of nickel into anodized aluminum oxide (AAO) template. The inter-branching of the wires provides rigidity of the structure, together with increase of the surface area of the current collector. The total surface area enhancement of the electrode was characterized by electrochemical passivation of the nickel nanowires and reached values up to 60x for 3 μm-long 3D nanoscaffolds. Additionally, we present results of electrodeposition of thin films of electrolytic manganese dioxide (EMD) on our 3D current collector and their activity as battery electrodes. This shows the potential of the 3D Ni-meshes for cheap fabrication of high power density electrodes for thin-film lithium-ion batteries. J. F. M. Oudenhoven, L. Bagetto, P. H. L. Notten, Adv. Energy Mater., 2011, 1, p. 10-33.J.Vanpaemel, A. M. Abd-Elnaiem, S. De Gendt, P. Vereecken, J. Phys. Chem. C, 2015, 119 (4), pp 2105-2112 Figure 1

Rheological phase reaction synthesis of Co-doped LiMn2O4 octahedral particles

Co-doped LiMn2O4 octahedral particles were prepared by the rheological phase reaction using LiOH·H2O, electrolytic manganese dioxide (EMD), and Co3O4 as starting materials. The crystal structure and morphology of as-synthesized compound were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The XRD results showed that the obtained powders were single-phase with a cubic spinel structure (Fd3m space group). SEM micrograph revealed that the particles possessed an octahedral morphology, with an average particle size of about 1–2 μm. Electrochemical test results showed that this Co-doped LiMn2O4 could deliver high specific capacity and good cycling stability, for the initial discharge capacity was 112.5 mAh g−1 and the discharge capacity remained to keep 100 mAh g−1 at 100th cycle, with an average capacity fade rate about 0.1 % per cycle.

BATTERY RECYCLING: EFFECT OF CURRENT DENSITY ON MANGANESE RECOVERY THROUGH ELECTROLYTIC PROCESS

This work aims to verify the possibility of using depleted batteries as a source of manganese dioxide applying the electrolytic process. An electrolyte solution containing the following metal ions was used: Ca (270 mgL-1), Ni (3.000 mgL-1), Co (630 mgL-1), Mn (115.3 mgL-1), Ti (400 mgL-1) and Pb (20 mgL-1). The production of electrolytic manganese dioxide (EMD) was performed through electrolysis at 98 °C (± 2 °C) applying different current densities (ranging from 0.61 A.dm-2 to 2.51 A.dm-2). The materials obtained were analyzed through X-ray fluorescence spectrometry, X-ray diffraction, specific surface area (BET) and scanning electron microscopy (SEM). The best results regarding the current efficiency, purity grade and specific surface area were obtained with a current density ranging between 1.02 A.dm-2 and 1.39 A.dm-2. The allotropic eMnO2 variety was found in all tests.

Production of electrolytic manganese dioxide from purified solutions after the leaching of manganese-bearing slurry

The production of electrolytic manganese dioxide from purified solutions after the leaching of manganese-bearing slurry is investigated. The influence of the anodic current density on the electrolysis of manganese-bearing solutions is determined. The preliminary purification of manganese-bearing solutions before electrolysis is discussed. Purification of the solution at pH 6.5–7.0 ensures the maximum deposition of all the impurities that interfere with electrolysis: copper, zinc, nickel, cobalt, aluminum, phosphorus, arsenic, antimony, iron (III), and iron (II). After impurity deposition, the pulp is filtered; the hydrate deposits are washed; and the filtered liquid is sent for electrolysis to obtain electrolytic manganese dioxide. The samples of electrolytic manganese dioxide are studied by means of X-ray fluorescent analysis, X-ray phase analysis, and scanning electron microscopy. The results show that the electrolytic manganese dioxide obtained in the laboratory with anodic current density I a = 150–200 A/m2 meets all the requirements on a highly active product: the content of the basic component (MnO2) in the experiments is 95.0–96.5 wt %.

Electrodeposition of Sea Urchin and Cauliflower‐like Nickel‐/Cobalt‐Doped Manganese Dioxide Hierarchical Nanostructures with Improved Energy‐Storage Behavior

AbstractTransforming the existing Zn–MnO2 primary battery into a secondary battery with enhanced storage behavior and a low cost is of significant interest. Such technology could underpin future energy‐storage development. To acquire this, doped electrolytic manganese dioxide (EMD) with hierarchical nanoarchitectures have been employed as a cathode in the Zn–MnO2 system. EMD is synthesized from manganese sulfate in a sulfuric acid bath with in situ doping of nickel and cobalt ions individually. Sea‐urchin‐shaped EMD has been obtained with nickel as a dopant, whereas cauliflower‐ and pyramidal‐shaped hierarchical nanostructures are observed with cobalt as a dopant, using a facile galvanostatic method without employing any template or surfactant. The structural studies indicated that all EMD samples (in the absence and presence of dopants) are predominantly composed of gamma‐type manganese dioxide; however, the peak intensity increased with increasing concentration of the dopants. The electrochemical results revealed that the Co‐doped EMD composite played a crucial role in increasing the storage capacity of the Zn–MnO2 battery, whereas the Ni‐doped EMD composite resulted in improved longevity compared the Co‐doped and undoped counterparts. The EMD composites individually doped with Ni and Co resulted in improved storage behaviors of 395 and 670 mA h g−1, respectively, against the undoped sample which is 220 mA h g−1, implying that the presence of Co3O4 and mesoporous nanostructured surfaces enhanced the fast kinetics of electrochemical reactions.

A Synergistic System for Lithium–Oxygen Batteries in Humid Atmosphere Integrating a Composite Cathode and a Hydrophobic Ionic Liquid‐Based Electrolyte

Moisture in air is a major obstacle for realizing practical lithium‐air batteries. Here, we integrate a hydrophobic ionic liquid (IL)‐based electrolyte and a cathode composed of electrolytic manganese dioxide and ruthenium oxide supported on Super P (carbon black) to construct a promising system for Li‐O2 battery that can be sustained in humid atmosphere (RH: 51%). A high discharge potential of 2.94 V and low charge potential of 3.34 V for 218 cycles are achieved. The outstanding performance is attributed to the synergistic effect of the unique hydrophobic IL‐based electrolyte and the composite cathode. This is the first time that such excellent performance is achieved in humid O2 atmosphere and these results are believed to facilitate the realization of practical lithium‐air batteries.

A simple and mass production preferred solid-state procedure to prepare the LiSixMgxMn2−2xO4 (0≤x≤0.10) with enhanced cycling stability and rate capability

We presented a simple and mass production preferred solid-state procedure to prepare the LiSixMgxMn2−2xO4 (0 ≤ x ≤ 0.10) samples by using industrial electrolytic manganese dioxide (EMD), lithium carbonate, tetraethylorthosilicate (TEOS) and magnesium nitrate as raw materials. All the Si–Mg co-doped LiMn2O4 samples showed the intrinsic spinel structure without any other impurity phases. Among these samples, the LiSi0.05Mg0.05Mn1.90O4 was found to be optimal possessing regular crystal morphology with clean surfaces. Electrochemical tests showed that the LiSi0.05Mg0.05Mn1.90O4 could present excellent cycling stability and rate capability. It exhibited the initial discharge capacity of 121.3 mAh g−1 at 0.5 C between 3.20 and 4.35 V. After 100 cycles, the discharge capacity could still reach up to 113.8 mAh g−1 with capacity retention of 93.8%. Moreover, at the higher charge–discharge rate of 5.0 C, a high discharge capacity of 92.5 mAh g−1 was obtained while the undoped LiMn2O4 sample only exhibited 47.8 mAh g−1. These results indicated that the LiSi0.05Mg0.05Mn1.90O4 prepared by a simple and mass production preferred solid-state procedure in this work might promote the large-scale industrial production of LiMn2O4.

Electrolytic Manganese Dioxide Structural and Morphological Effects on Capacitive Performance

Step potential electrochemical spectroscopy (SPECS) has been applied to a range of different electrolytic manganese dioxide (EMD) samples to examine the effects that material composition, structure and morphology have on the performance of these materials as electrochemical capacitor electrodes. The applications of SPECS enabled deconvolution of the electrode behaviour into double layer and diffusional or pseudo-capacitive effects. The technique was even sensitive enough to resolve double layer charge storage associated with either the geometric or porous surface area. The relationships between each of the contributions to total capacitance and the EMD material properties have been described and discussed.

Faradaic and Non-Faradaic Contributions to the Power and Energy Characteristics of Electrolytic Manganese Dioxide for Electrochemical Capacitors

Step potential electrochemical spectroscopy (SPECS) has been applied to a range of different electrolytic manganese dioxide (EMD) samples to examine the changes in the charge storage mechanism as a function of the scan rate. The SPECS method allowed the charge storage contributions due to double layer and pseudo-capacitance to be decoupled. The charge storage mechanism has been shown to transition from predominantly pseudo-capacitive behavior to predominantly double layer behavior as the scan rate is increased. The relative contributions from each of these processes to the overall specific energy and power of each EMD samples has been analyzed and related to the properties of each material.

ASSESSMENT OF THE POSSIBILITY OF PRODUCING OF ELECTROLYTIC MANGANESE DIOXIDE FROM THE PURIFIED SOLUTIONS AFTER MANGANESE-SLUDGE LEACHING

Studies on the production of electrolytic manganese dioxide (EMD) from purified solutions after leaching of manganese sludge were held. The effect of anode current density on electrolysis manganese sulphate solutions is determined. The analysis of pre-treatment of manganese solutions before electrolysis was made. Conducting cleaning solution at pH 6,5–7,0 provides maximum deposition of impurities harmful to electrolysis of copper, zinc, nickel, cobalt, aluminum, phosphorus, arsenic, antimony, iron (III) and iron (II). After the deposition of impurities sludge is filtered, hydrate precipitate is washed, filtered liquid phase is sent to electrolysis to produce EDM. The EDM samples were examined using X-ray fluorescence, X-ray diffraction and scanning electron microscopy. The results showed that the EDM obtained under the laboratory conditions at an anodic current density in the range of I а = 150–200 A/m 2 , meets all the requirements for high-level product: mass fraction of the main component – МnО 2 is 95–96,5 % at the experiments.

Correlation among physical and electrochemical behaviour of nanostructured electrolytic manganese dioxide from leach liquor and synthetic for aqueous asymmetric capacitor.

An attempt has been made to correlate the differences in structural parameters, surface areas, morphology etc. with the electrochemical capacitive behaviour of the EMDs. The nanostructured electrolytic manganese dioxides (EMD) have been synthesized through electrodepositing MnO2 from two different leach liquors and a synthetic analogue thereof. The structural and chemical state was determined using X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) respectively. Multiplet structure determination led to estimates of the manganese valence states present in the EMD. The EMDs have been tested in an asymmetric capacitor which we have developed. This used activated carbon as the negative electrode and the various EMDs as the positive electrode. Aqueous 2 M NaOH solution was used as the electrolyte. The capacitor achieved 1.6 V corresponding to a capacitance of ∼50 F g(-1) of the EMDs from leach liquors. The EMD derived from the synthetic solution showed an inferior capacitance of 25 F g(-1). Extended cycling (2000 cycles), showed 100% capacity retention was achieved for one EMD produced from the leach liquor derived from low-grade manganese ore/residue. This outstanding capacitor performance was correlated with the presence of a nanofibrous morphology. These findings open up the possibility of extracting a high performance EMD product from a low cost, low-grade source of manganese.

Electrochemical Behavior of Electrolytic Manganese Dioxide in Aqueous KOH and LiOH Solutions: A Comparative Study

As an inexpensive and high capacity oxidant, electrolytic manganese dioxide (γ-MnO2) is of interest as a cathode for secondary aqueous batteries. Electrochemical behavior of γ-MnO2 was characterized in aqueous 5.0 M KOH and LiOH solutions, and found to depend strongly upon cation identity. In LiOH and mixed LiOH / KOH solutions, Li-ion intercalation appeared to operate in competition with proton intercalation, being favored at higher [Li+] and, for mixed electrolytes, lower sweep rates. Electrochemical and in situ X-ray diffraction data indicated that γ-MnO2 underwent a chemically irreversible transformation upon the first reduction in LiOH solution, while in KOH solution, structure was largely unchanged after the first cycle. These experiments with γ-MnO2 as well as with a closely-related, ramsdellite-like sample, suggest that depending on sample morphology/rate capability, the irreversible process proceeds either through a solid-solution reaction or a two-phase reaction followed by a solid-solution reaction. While discharge capacity and capacity retention during galvanostatic cycling of γ-MnO2 were worse in LiOH than in KOH solution, some improvement was noted in a mixed LiOH/KOH solution.

Low-temperature direct synthesis of layered m-LiMnO2 for lithium-ion battery applications

Layered monoclinic LiMnO2 is a potential low-cost alternative to LiCoO2 cathode for lithium-ion batteries. However, its application is limited partly because it cannot be synthesized easily. In this work, we successfully synthesized phase-pure layered LiMnO2 in a one-step low-temperature process using electrolytic manganese dioxide (EMD) as the manganese precursor at 450 °C in Ar atmosphere by a carbothermal reduction method. The initial carbon to manganese ratio has to be optimized to remove impurities. The particle size of the material is between 40 and 60 nm. The synthesized sample shows an initial reversible capacity of about 180 mAh g−1. The synthesis method is further applied to make boron-doped samples, which significantly enhanced the stability of the material, especially at high temperature. The boron-doped samples maintain a capacity of 150 mAh g−1 for 100 cycles and give a capacity of about 100 mAh g−1 at a current of 1000 mA g−1 (equivalent to 10C rate). The ability to directly synthesize the material at low temperature is crucial because it allows further improvement of material performances through methods such as surface coating and the use of electrolyte additives to reduce surface reaction and Mn-dissolution.

Co/Mo bimetallic addition to electrolytic manganese dioxide for oxygen generation in acid medium

An efficient electrocatalyst comprising inexpensive and earth-abundant materials for the oxygen evolution reaction (OER) is crucial for the development of water electrolysis. In this work, in-situ addition of cobalt/molybdenum ions to the electrolytic manganese dioxide has been shown to be beneficial for the OER in acid solution as its overpotential performed better (305 mV) than that of the commercial DSA® (341 mV) at 100 mA cm−2. The OER was investigated at ambient temperature in 2 M H2SO4 solution on the modified EMD (MnMoCoO) electrodes. The energy efficiency of the MnMoCoO electrodes improved significantly with the amount of Co in the plating solution. For the electrodeposited catalysts, physico-chemical and electrochemical measurements were conducted including static overpotentials. The better performance of the modified EMD was attributed to an improved charge transfer resistance (Rct; 0.290 Ω cm2), average roughness factor (rf; 429) and decrease in water content in the electrodeposited catalysts. The kinetic parameters obtained on MnMoCoO catalysts were compared and discussed according to the cobalt concentration.

Electrochemical Activities of Electrolytic Manganese Dioxide (EMD) as a Cathode Electrode for Lithium Air Batteries

Electrochemical Activities of Electrolytic Manganese Dioxide (EMD) as a Cathode Electrode for Lithium Air Batteries

ChemInform Abstract: Electrolytic Manganese Dioxide (EMD): A Perspective on Worldwide Production, Reserves and Its Role in Electrochemistry

AbstractReview: 215 refs.

Spinel MnO2 As a Rapidly Oxidizing Cathode Material for Fuel Cell/Battery Systems

The fuel cell/battery (FCB) system combines the working principle of an alkaline battery with an alkaline fuel cell. As anode material, a metal hydride is chosen, which is also found in nickel-metal hydride batteries. This mischmetal can be charged both electrochemically and under hydrogen atmosphere. As a cathode material, manganese dioxide (MnO2) is utilized. We have shown previously that MnO2can, under the right conditions, be cycled electrochemically and recharged from its discharged form (MnOOH) via oxidation in an oxygen saturated alkaline solution. MnO2 can have different crystalloid structures, depending on the allocation of the MnO6 octahedra. In previous work, we have mostly focused on electrolytic manganese dioxide (EMD), also called γ-MnO2, in which the MnO6 octahedra are aligned to create a combination of 2x1 and 1x1 tunnel structures. In this work, however, we investigated the possibility of utilizing spinel MnO2, also known as λ-MnO2, as an alternative To obtain λ-MnO2, we first synthesized LiMn2O4 via a solid state reaction of EMD with LiOH. The result was a spinel structure with Li+ ions occupying the tetrahedral sites. The lithium ions can then be removed chemically in a diluted acid, thereby leaving the solid in a spinel structure. We then analyzed the performance of λ-MnO2 for the application in FCB and compared it with γ-MnO2. For this, we manufactured half-cells, cycled the samples electrochemically and recharged MnOOH in an oxygen-saturated alkaline solution in an autoclave. The cathodes were manufactured through a pasting method with a slurry consisting of MnO2, carbon black (CB) and ethylene-vinyl acetate (EVA) in a weight ratio of 100:15:10 dissolved in xylene. Half-cells were assembled with nickel foam and Hg/HgO as counter and reference electrode, respectively, polypropylene as separator and a 6M KOH solution as electrolyte. Compared with γ-MnO2, λ-MnO2 shows a similar capacity during the first discharge, but loses a high capacity between the first and second discharge. Afterwards, capacity loss is considerably lower and at around the same rate as for γ-MnO2. However, in terms of rechargeability with oxygen, λ-MnO2 shows superior results. In an oxygen-saturated 6M KOH solution under 1MPa pressure, after 1 hour, the fully discharged λ-MnO2 recharged to 15% of its maximum theoretical capacity, compared to 10% of γ-MnO2. These are very promising results on our target of combining the advantages of fuel cells with batteries. Further research is thus being conducted, mainly focusing on improving rechargeability of λ-MnO2.

Electrodeposition of Thick MnO2 Films on Restrictive Substrates

Lithiated electrolytic manganese dioxide (EMD or ƴ-MnO2) is considered to be a promising positive electrode material for rechargeable lithium ion batteries due to its relatively high specific capacity and long-term cyclability along with its low cost and low toxicity [1,2]. Conformal deposition of thick EMD material is needed for its application in 3D solid state batteries. However, during the anodic electrodeposition of manganese dioxide, the underlying current collector is oxidized at the same potential range as the EMD deposition, e.g. titanium nitride (TiN) or aluminum (Al) current collectors. In this work we investigate the use of thin coatings prepared by vapor phase of wet chemical deposition to protect the current collector from the undesirable oxidation and allow the deposition of thick MnO2 films with good adhesion properties. We show conformal deposition of MnO2 films up to 600 nm thick from aqueous bath on high aspect ratio silicon pillar arrays. Silicon pillars were covered with 20 nm TiN which acts as a diffusion barrier of Li ions into Si. Reversible insertion and extraction of Li+ into thick EMD is demonstrated on both planar and 3D substrates with an expected capacity increase associated with the surface area gain for 3D substrates. We also demonstrate the application of a thin coating to enhance the adhesion between the electrodeposited MnO2 cathode material and aluminum surface, including Al foil, opening doors towards its use in flexible batteries.[1] M. Thackeray, Prog. Solid St. Chem., 25, 1997 [2] A. Etman, A. Radisic, M. Emara, C. Huyghebaert, P.Vereecken, J. Phys. Chem. C, 118 (19), 2014 Figure 1

Electrolyte Effects on the Electrochemical Behavior of Electrolytic Manganese Dioxide in Alkaline Aqueous Media

Electrolytic manganese dioxide (EMD) is the cathode material typically used in primary alkaline cells, owing to its low cost and relatively high gravimetric capacity. These qualities also make it attractive as a cathode for secondary cells, though unfortunately its cycle-life is relatively short. The cycle-life can be improved under certain conditions, e.g. at limited depth of discharge [1]; there also reports of improved cycleability in LiOH solutions or against non-zinc electrodes [2]. We have investigated the effects of electrolyte composition on the electrochemical properties of EMD with cyclic voltammetry and galvanostatic cycling. More particularly, we focused on LiOH and KOH electrolytes, with ZnO present or absent. The structural evolution of the material during electrochemical cycling was studied using in situ synchrotron x-ray diffraction. While the structure of the EMD appears to remain largely intact after a single cycle in KOH solution, it undergoes an irreversible transformation at low depths of discharge when reduced in lithium hydroxide solutions. Both electrochemical and diffraction measurements indicate this transformation was complete within the first reduction, though the material undergoes further structural evolution with extended cycling. The electrochemical behavior of ramsdellite MnO2, the prototypical structure for EMD, was also examined in a LiOH electrolyte as a point of comparison. Ramsdellite underwent an irreversible transformation at low depths of discharge in a manner similar to that observed for EMD. The evolution of the diffraction pattern of the ramsdellite upon electrochemical reduction was very similar to that reported for chemically reduced ramsdellite in organic media [3]. In situ measurements with zincate-containing electrolyte showed ZnMn2O4 (hetaerolyte) to form sooner in LiOH solutions than KOH solutions. Curiously, hetaerolyte underwent some structural changes upon re-oxidation and we will provide some possible interpretations of this observation. Short-term (<30 cycles) capacity and cycleability trends observed as a function of the various electrolyte compositions and potential limits will also be presented. [1] K. Kordesch, J. Gsellmann, M. Peri, K. Tomantschger, R. Chemelli Electrochim. Acta 1981, 26, 1495-1504. [2] M. Minakshi Electrochem. Solid-State Lett. 2010, 13, A125-A127. [3] M.M. Thackeray, M.H. Rossouw, R.J. Gummow, D.C. Liles, K. Pearce, A. De Kock, W.I.F. David, S. Hull Electrochim. Acta 1993, 38, 1259-1267.

Ion-Transport Characteristics of Alkaline Battery Cathodes Containing Different Graphitic Additives

Yearly demand for primary alkaline batteries is around US$5 billion. Even though it is a mature technology, continued performance improvement is still possible. In common with other types of batteries, the performance of alkaline batteries is strongly affected by the composition and microstructure of the electrodes, especially the cathode. Naturally, in trying to optimize an electrode there are trade-offs between the capacity or amount of active material, and the volume fractions of conductive additive (carbon) and pores, which are each needed to transport charge. This work builds on our prior work in directly measuring transport properties of electrodes [1-2]. We focus on understanding ion transport in the alkaline cathode, which is composed of EMD (electrolytic manganese dioxide), graphitic carbon, and electrolyte-filled pores. The effects of varying carbon type, carbon amount, and overall porosity on the ionic conductivity and tortuosity were studied. The correlations between ion transport and the microstructure and electronic conductivity were investigated as well. Tested carbons included a variety of common graphite additives from TIMCAL as well as graphene. Multiple analysis tools were used, including SEM/FIB determination of microstructure, ion-transport experiments, and multi-probe determination of electronic conductivities. It was found that highly compressible expanded graphites like BNB90 actually have a more deleterious effect on overall ionic conductivity that do other additives. This suggests a tradeoff between ionic and electronic conductivity performance in the choice of graphitic additive. Furthermore, the degree of anisotropy of ion transport in the cathode for different conditions was investigated for samples containing EMD and BNB90 additive. Anisotropy of the structure of the graphite, caused by pellet compression, was observed by SEM. It was found that tortuosity is lower and ionic conductivity is higher in the direction orthogonal to the direction of compression. [1] Zacharias et al., J. Electrochem. Soc. 160, A306-A311 (2013). [2] Peterson and Wheeler, J. Electrochem. Soc. 161, A2175-A2181 (2014). Figure 1