Understanding the Electrochemical Mechanism of K-αMnO<sub>2</sub> for Magnesium Battery Cathodes

Arthur, Timothy S.; Zhang, Ruigang; Ling, Chen; Glans, Per‐Anders; Fan, Xudong; Guo, Jinghua; Mizuno, Fuminori

doi:10.1021/am5015327

Cited by 138 publications

(201 citation statements)

References 28 publications

(42 reference statements)

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“…11,79,80 Figure 6a shows the X-ray transparent operando sXAS cell, electrochemical data taken using the cell, and sXAS data Considering the current sXAS data and analysis that compliment previous studies, a direct electrochemical reduction of the Mg-dimer is an unlikely route to form Mg metal.…”

Section: And Batteries 62supporting

confidence: 71%

X-ray spectroscopy of energy materials under in situ/operando conditions

Crumlin

Liu

Bluhm

et al. 2015

Journal of Electron Spectroscopy and Related Phenomena

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A perspective and brief review of in situ/operando X-ray spectroscopic techniques with focus on energy materials is presented, including discussion on current status, choice of cells and suitable X-ray energy range. Initial discussion focuses on the scientific advancement achieved using ambient pressure X-ray photoelectron spectroscopy (APXPS) at the solid/gas interface, and then progresses through the techniques evolution to probe the liquid/vapor and the emerging solid/liquid interface. This is followed by an overview of soft X-ray adsorption spectroscopy (sXAS) for energy science using both window and windowless cell configurations. Concluding remarks provide a future outlook for where the authors believe these techniques and class of science will progress towards.

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Section: And Batteries 62supporting

confidence: 71%

X-ray spectroscopy of energy materials under in situ/operando conditions

Crumlin

Liu

Bluhm

et al. 2015

Journal of Electron Spectroscopy and Related Phenomena

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“…Capacity fading still remains a problem, however, as in each case the capacity fell below 50 mA h g −1 within ten cycles. Although EIS results show the amorphous layer causes an increase in charge transfer resistance with cycling [228], this layer is apparently thin enough (on the order of 1 nm [227]) that its contribution is negligible compared to the well-known issue of Mn dissolution and electrolyte decomposition catalyzed by the active material.…”

Section: Reviewmentioning

confidence: 93%

“…An interesting study combined microscopy and spectroscopy to provide evidence for conversion as the primary charge transfer mechanism in K + -stabilized α-MnO 2 [227]. TEM images showed the progressive formation of an amorphous layer on the originally crystalline nanorods (Fig.…”

Section: Reviewmentioning

confidence: 99%

Beyond Li-ion: electrode materials for sodium- and magnesium-ion batteries

2015

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to develop and install renewable energy harvesting technologies [3]. However, their successful implementation will be dependent on reliable and robust storage devices since harvesting solar and wind energy is inherently intermittent and the majority of consumption targets cannot be readily tethered to the grid.As energy storage devices, batteries possess high portability, high energy density, high Coulombic efficiency, and long cycle life. They are ideal power sources for portable devices, automobiles, and backup power supplies; accordingly, batteries power nearly all of our mobile electronics and are used to improve the efficiency of hybrid electric vehicles [4,5]. Unfortunately, considerable improvements in performance are still required in order to meet the demands of advanced portable devices and achieve energy sustainability (e.g., through smart grid and electric vehicle technologies) [6]. These enduring needs have driven intensive research investments. While efforts have been successful, there is still significant room for improvement regarding the development and understanding of electrode materials [7]. The overall capacity and potential cycling window of many electrode materials are limited to prevent degradation over long term cycling. In addition to exploring new electrode materials, there have been strong efforts to improve those that are already utilized. Expense reduction is a priority as approximately 23% and 8% of the overall battery pack costs stem from the respective cathode and anode active materials alone [8].An alkali-ion battery consists of several electrochemical cells connected in parallel and/or in series to provide a designated current or voltage. Each electrochemical cell has two electrodes separated by an electrolyte that is electrically insulating but ionically conductive. During discharge, when the alkali-ion battery operates as a galvanic cell, alkali ions exit the negative electrode (typically carbon) and insert themselves into the positive electrode while electronsThe need for economical and sustainable energy storage drives battery research today. While Li-ion batteries are the most mature technology, scalable electrochemical energy storage applications benefit from reductions in cost and improved safety. Sodium-and magnesium-ion batteries are two technologies that may prove to be viable alternatives. Both metals are cheaper and more abundant than Li, and have better safety characteristics, while divalent magnesium has the added bonus of passing twice as much charge per atom. On the other hand, both are still emerging fields of research with challenges to overcome. For example, electrodes incorporating Na + are often pulverized under the repeated strain of shuttling the relatively large ion, while insertion and transport of Mg 2+ is often kinetically slow, which stems from larger electrostatic forces. This review provides an overview of cathode and anode materials for sodium-ion batteries, and a comprehensive summary of research on cathodes for magnesium-ion batteries. In additi...

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“…7-10 Various MnO 2 polymorphs, including α-, stabilized α-, β-, γ-, and δ-MnO 2 , have also been explored with varying degrees of effectiveness. [11][12][13] The most successful polymorphs were α-MnO 2 nanorods with high surface area and δ-MnO 2 (birnessite). Mg 2+ insertion into the birnessite structure is made possible by the charge screening effect of the crystal water molecules present between 3 MnO 6 layers.…”

Section: Introductionmentioning

confidence: 99%

On the Utility of Spinel Oxide Hosts for Magnesium-Ion Batteries

Knight

Therese

Manthiram

2015

ACS Appl. Mater. Interfaces

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There is immense interest to develop Mg-ion batteries, but finding suitable cathode materials has been a challenge. The spinel structure has many advantages for ion insertion and has been successfully used in Li-ion batteries. We present here findings on the attempts to extract Mg from MgMn2O4-based spinels with acid (H2SO4) and with NO2BF4. The acid treatment was able to fully remove all Mg from MgMn2O4 by following a mechanism involving the disproportionation of Mn(3+), and the extraction rate decreased with increasing cation disorder. Samples with additional Mg(2+) ions in the octahedral sites (e.g., Mg1.1Mn1.9O4 and Mg1.5Mn1.5O4) also exhibit complete or near complete demagnesiation due to an additional mechanism involving ion exchange of Mg(2+) by H(+), but no Mg could be extracted from MgMnAlO4 due to the disruption of Mn-Mn interaction/contact across shared octahedral edges. In contrast, no Mg could be extracted with the oxidizing agent NO2BF4 from MgMn2O4 or Mg1.5Mn1.5O4 as the electrostatic repulsion between the divalent Mg(2+) ions prevents Mg(2+) diffusion through the 16c octahedral sites, unlike Li(+) diffusion, suggesting that spinels may not serve as potential hosts for Mg-ion batteries. The ability to extract Mg with acid in contrast to that with NO2BF4 is attributed to Mn dissolution from the lattice and the consequent reduction in electrostatic repulsion. The findings could provide insights toward the design of Mg hosts for Mg-ion batteries.

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Understanding the Electrochemical Mechanism of K-αMnO₂ for Magnesium Battery Cathodes

Cited by 138 publications

References 28 publications

X-ray spectroscopy of energy materials under in situ/operando conditions

X-ray spectroscopy of energy materials under in situ/operando conditions

Beyond Li-ion: electrode materials for sodium- and magnesium-ion batteries

On the Utility of Spinel Oxide Hosts for Magnesium-Ion Batteries

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Understanding the Electrochemical Mechanism of K-αMnO2 for Magnesium Battery Cathodes

Cited by 138 publications

References 28 publications

X-ray spectroscopy of energy materials under in situ/operando conditions

X-ray spectroscopy of energy materials under in situ/operando conditions

Beyond Li-ion: electrode materials for sodium- and magnesium-ion batteries

On the Utility of Spinel Oxide Hosts for Magnesium-Ion Batteries

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Product

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Understanding the Electrochemical Mechanism of K-αMnO₂ for Magnesium Battery Cathodes