Ionic conductivity of a single porous MnO<sub>2</sub>mesorod at controlled oxidation states

Plett, Timothy S.; Gamble, T.; Gillette, Eleanor; Lee, Sang Bok; Siwy, Zuzanna S.

doi:10.1039/c5ta03196f

Cited by 5 publications

(2 citation statements)

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“…As revealed by molecular dynamics simulations, a larger number of lithium ions stayed adsorbed close to the surface compared to sodium and potassium ions, which led to lowest rectification in lithium chloride. Recent work has also been done on lithium transport through nano-fabricated battery materials 47,48 (manganese oxide), which revealed this cathode material, at various oxidation states, possesses nanoconstrictions with excess surface charge. However, these experiments were conducted in aqueous solutions, which are not ideal or representative of lithium ion battery technology, 49 which relies on use of organic solvents to resist electrode degradation and improve capacity retention and cycle life.…”

Section: Introductionmentioning

confidence: 99%

Rectification of nanopores in aprotic solvents – transport properties of nanopores with surface dipoles

et al. 2015

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Nanopores have become a model system to understand transport properties at the nanoscale. We report experiments and modeling of ionic current in aprotic solvents with different dipole moments through conically shaped nanopores in a polycarbonate film and through glass nanopipettes. We focus on solutions of the salt LiClO4, which is of great importance in modeling lithium based batteries. Results presented suggest ion current rectification observed results from two effects: (i) adsorption of Li(+) ions to the pore walls, and (ii) a finite dipole moment rendered by adsorbed solvent molecules. Properties of surfaces in various solvents were probed by means of scanning ion conductance microscopy, which confirmed existence of an effectively positive surface potential in aprotic solvents with high dipole moments.

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Section: Introductionmentioning

confidence: 99%

Rectification of nanopores in aprotic solvents – transport properties of nanopores with surface dipoles

et al. 2015

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“…48 The rod contained negative surface charges due to the presence of hydroxyl groups, and the rectification properties were modulated by intercalated lithium ions. 49 Further tests were conducted to determine if exposing pores with PMMA gel to a liquid electrolyte only from one side is sufficient to observe an enhanced ionic transport. The schematic in Fig.…”

Section: Resultsmentioning

confidence: 99%

Ion transport in gel and gel–liquid systems for LiClO₄-doped PMMA at the meso- and nanoscales

et al. 2017

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Solid and gel electrolytes offer significant advantages for cycle stability and longevity in energy storage technologies. These advantages come with trade-offs such as reduced conductivity and ion mobility, which can impact power density in storage devices even at the nanoscale. Here we propose experiments aimed at exploring the ion transport properties of a hybrid electrolyte system of liquid and gel electrolytes with meso and nanoscale components. We focus on single pore systems featuring LiClO-propylene carbonate and LiClO-PMMA gel, which are model electrolytes for energy storage devices. We identified conditions at which the systems considered featured rectifying current-voltage curves, indicating a preferential direction of ion transport. The presented ion current rectification suggests different mechanisms arising from the unique hybrid system: (i) PMMA structure imposing selectivity in fully immersed systems and (ii) ionic selectivity linked to ion sourcing from media of different ionic mobility. These mechanisms were observed to interplay with ion transport properties linked to nanopore structure i.e. cylindrical and conical.

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Microtube‐Membrane Methodology for Electrochemical Synthesis and Study of Electroactive and Ionically Conductive Materials, and the Conductivity of MnO₂

Experton

Wang

2018

ChemElectroChem

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A membrane-based methodology for electrochemical synthesis and study of electroactive and ionically conductive materials is described. The Li + -intercalation material MnO 2 was used to demonstrate this methodology. The membrane was a polymeric support containing monodisperse gold microtubes (diameter 600 nm) that span the thickness of the membrane. Bipolar electrochemical synthesis of MnO 2 , from Mn 2 + solutions, was conducted across this membrane, resulting in deposition of monodisperse, hemispherical MnO 2 particles at the open ends of the tubes on one face of the membrane. The resulting microtube/MnO 2 composite membrane makes a convenient construct for investigating the transport properties of the MnO 2 particles. This was accomplished by mounting the membrane in a U-tube cell, placing electrolyte solutions on either side, and driving an ionic current through the membrane. The ionic conductivity of MnO 2 was measured in this way, and found to be 40 � 10 μS cm À 1 when LiCl or LiClO 4 solutions were used as the electrolyte. The mechanism of ionic conductivity through these MnO 2 particles is discussed.[a] J. Figure 1. a) A gold-microtube membrane, and b) bipolar synthesis/deposition of MnO 2 across such a membrane. Dimensions are not to scale.

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Ionic conductivity of a single porous MnO₂mesorod at controlled oxidation states

Abstract: The ionic conductivity of porous MnO2 at the nanoscale is not well understood, despite possible importance in battery charging/discharging processes.

Cited by 5 publications

References 21 publications

Rectification of nanopores in aprotic solvents – transport properties of nanopores with surface dipoles

Rectification of nanopores in aprotic solvents – transport properties of nanopores with surface dipoles

Ion transport in gel and gel–liquid systems for LiClO₄-doped PMMA at the meso- and nanoscales

Microtube‐Membrane Methodology for Electrochemical Synthesis and Study of Electroactive and Ionically Conductive Materials, and the Conductivity of MnO₂

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Ionic conductivity of a single porous MnO2mesorod at controlled oxidation states

Abstract: The ionic conductivity of porous MnO2 at the nanoscale is not well understood, despite possible importance in battery charging/discharging processes.

Cited by 5 publications

References 21 publications

Rectification of nanopores in aprotic solvents – transport properties of nanopores with surface dipoles

Rectification of nanopores in aprotic solvents – transport properties of nanopores with surface dipoles

Ion transport in gel and gel–liquid systems for LiClO4-doped PMMA at the meso- and nanoscales

Microtube‐Membrane Methodology for Electrochemical Synthesis and Study of Electroactive and Ionically Conductive Materials, and the Conductivity of MnO2

Contact Info

Product

Resources

About

Ionic conductivity of a single porous MnO₂mesorod at controlled oxidation states

Ion transport in gel and gel–liquid systems for LiClO₄-doped PMMA at the meso- and nanoscales

Microtube‐Membrane Methodology for Electrochemical Synthesis and Study of Electroactive and Ionically Conductive Materials, and the Conductivity of MnO₂