Chemical Charging on a MnO2 Electrode of a Fuel Cell/Battery System in a Highly O2-Dissolved Electrolyte

Choi, Bokkyu; Panthi, Dhruba; Kwon, Young‐Uk; Tsutsumi, Atsushi

doi:10.1016/j.electacta.2015.02.023

Cited by 7 publications

(6 citation statements)

References 29 publications

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“…11 As the positive electrode, manganese dioxide (MnO 2 ) has been chosen for application in the FCB system because discharged MnO 2 (i.e., MnOOH) can be re-oxidized with oxygen. [12][13][14] Using MnO 2 provides several advantages, such as low cost, high abundance, and environmental compatibility. [15][16][17] MnO 2 is also commonly used in primary (i.e., non-rechargeable) alkaline household batteries, highlighting its benefits but also indicating its main shortcoming: poor recharge ability.…”

mentioning

confidence: 99%

Morphology and Electrochemical Properties of α-, β-, γ-, and δ-MnO₂Synthesized by Redox Method

Musil¹,

Choi²,

Tsutsumi³

2015

J. Electrochem. Soc.

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The crystal structures and electrochemical properties of α-, β-, γ-, and δ-MnO 2 , synthesized by a redox method under various conditions, were studied for the application of MnO 2 as a positive electrode in a fuel cell/battery (FCB) system. The effects of potassium ion concentration (0-10 M) and temperature (60-160 • C) on the morphology of synthesized MnO 2 were investigated by X-ray diffraction, scanning electron microscopy, and the Brunauer-Emmett-Teller method. In addition, the charge and discharge characteristics, and life cycle performance of MnO 2 as a positive electrode in an FCB system, were investigated by sweep voltammetry and potentiometry. The results indicate that four different crystal structures were obtained by different synthesis conditions: three tunnel structures (α-, β-, and γ-MnO 2 ) and one layered structure (δ-MnO 2 ). The effects of precipitation conditions were mapped and summarized in a phase diagram. Electrochemical testing showed that MnO 2 with small tunnel structures (i.e., βand γ-MnO 2 ) exhibit better life cycle performance than either large tunnel structure α-MnO 2 or layered δ-MnO 2 . Based on XRD analysis carried out after cycling, a schematic diagram is proposed to explain the degradation of the different MnO 2 compounds.

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confidence: 99%

Morphology and Electrochemical Properties of α-, β-, γ-, and δ-MnO₂Synthesized by Redox Method

Musil¹,

Choi²,

Tsutsumi³

2015

J. Electrochem. Soc.

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“…As for EA-aminated samples, a three-stage decomposition pattern was observed. The first weight loss was because of the moisture adsorbed on the aminated samples, showing the hydrophilic nature of the sheets after amination (Choi et al, 2015). Again, the decomposition peak of GMA side chains disappeared which confirmed the successful amination reaction.…”

Section: Thermal Propertiesmentioning

confidence: 75%

“…The GMA-grafted sample showed three-stage decomposition behavior. Degradation of glycidyl and carboxyl groups of GMA side chains appeared at 228 and 313 • C, respectively (Choi et al, 2015). Like the pristine nanofibers, the final decomposition stage at 455 • C was for the thermal decomposition of the main s-PP backbone.…”

Section: Thermal Propertiesmentioning

confidence: 95%

Carbon Dioxide Adsorption on Grafted Nanofibrous Adsorbents Functionalized Using Different Amines

et al. 2019

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“…14 As an alternative, our group has used γ-MnO 2 for the application in FCB systems because this crystal structure was found to have a good redox reaction cyclability if the discharge was cutoff at a potential of −0.4 V vs. Hg/HgO. 2,7,15 Only when a low discharge potential of −0.9 V vs. Hg/HgO was set, inactive Mn 3 O 4 was formed, leading to poor redox reaction cyclability. 2 However, the reaction rate of chemical charging (Eq.…”

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λ-MnO₂Positive Electrode for Fuel Cell/Battery Systems

Musil

Choi

Tsutsumi

2016

J. Electrochem. Soc.

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The possibility of replacing λ-MnO2 with previously used γ-MnO2 in the positive electrodes of fuel cell/battery (FCB) systems was analyzed. Samples were evaluated in three different modes: In fuel cell mode, the oxygen reduction reaction rate was measured at an elevated pressure of 1.0 MPa. In battery mode, the electrodes were electrochemically cycled at different rates to assess their proton diffusion. Finally, in FCB mode, the discharged electrodes were chemically charged with oxygen for one hour to quantify the chemical charge rate. For all modes, X-ray diffraction analysis was conducted to assess the crystal stability of both species. λ-MnO2 was found to exhibit a considerably better catalytic capability for oxygen reduction reaction and could be chemically charged more quickly with oxygen than γ-MnO2. It is proposed that these results were caused by a lower charge transfer resistance in λ-MnO2. However, γ-MnO2 showed better proton diffusivity than λ-MnO2, mainly owing to its higher surface area. In terms of crystal stability, λ-MnO2 was found to be superior to γ-MnO2, thus making it a promising positive electrode material for FCB systems.

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Chemical Charging on a MnO2 Electrode of a Fuel Cell/Battery System in a Highly O2-Dissolved Electrolyte

Cited by 7 publications

References 29 publications

Morphology and Electrochemical Properties of α-, β-, γ-, and δ-MnO₂Synthesized by Redox Method

Morphology and Electrochemical Properties of α-, β-, γ-, and δ-MnO₂Synthesized by Redox Method

Carbon Dioxide Adsorption on Grafted Nanofibrous Adsorbents Functionalized Using Different Amines

λ-MnO₂Positive Electrode for Fuel Cell/Battery Systems

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Chemical Charging on a MnO2 Electrode of a Fuel Cell/Battery System in a Highly O2-Dissolved Electrolyte

Cited by 7 publications

References 29 publications

Morphology and Electrochemical Properties of α-, β-, γ-, and δ-MnO2Synthesized by Redox Method

Morphology and Electrochemical Properties of α-, β-, γ-, and δ-MnO2Synthesized by Redox Method

Carbon Dioxide Adsorption on Grafted Nanofibrous Adsorbents Functionalized Using Different Amines

λ-MnO2Positive Electrode for Fuel Cell/Battery Systems

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Product

Resources

About

Morphology and Electrochemical Properties of α-, β-, γ-, and δ-MnO₂Synthesized by Redox Method

Morphology and Electrochemical Properties of α-, β-, γ-, and δ-MnO₂Synthesized by Redox Method

λ-MnO₂Positive Electrode for Fuel Cell/Battery Systems