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

• Published in: ChemElectroChem Vol. 5; no. 20; pp. 3113 - 3120
• Main Authors: Experton, Juliette, Wu, Xiaojian, Wang, Gelan, Martin, Charles R.
• Format: Journal Article
• Language: English
• Published: Weinheim John Wiley & Sons, Inc 12.10.2018; ChemPubSoc Europe
• Subjects: bio-inspired; bipolar electrochemical synthesis; charge transport; Chemical synthesis; defects; electrochemistry; Electrolytes; energy storage (including batteries and capacitors); Gold; gold-microtube membranes; INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY; Ion currents; ionic conductivity; Lithium chloride; Manganese dioxide; Methodology; synthesis (novel materials); synthesis (scalable processing); synthesis (self-assembly); Tubes
• ISSN: 2196-0216; 2196-0216
• DOI: 10.1002/celc.201801010

A membrane‐based methodology for electrochemical synthesis and study of electroactive and ionically conductive materials is described. The Li+‐intercalation material MnO2 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 MnO2, from Mn2+ solutions, was conducted across this membrane, resulting in deposition of monodisperse, hemispherical MnO2 particles at the open ends of the tubes on one face of the membrane. The resulting microtube/MnO2 composite membrane makes a convenient construct for investigating the transport properties of the MnO2 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 MnO2 was measured in this way, and found to be 40±10 μS cm−1 when LiCl or LiClO4 solutions were used as the electrolyte. The mechanism of ionic conductivity through these MnO2 particles is discussed. A membrane‐based methodology for electrochemical synthesis and study of the Li+‐intercalation material MnO2 is described. The resulting gold microtube/MnO2 composite membrane makes a convenient construct for investigating the transport properties of the MnO2 particles. The ionic conductivity through these MnO2 particles was measured, and its mechanism is discussed.