Probing Porous Structure of Single Manganese Oxide Mesorods with Ionic Current

Abstract

Characterization of materials in confined spaces, rather than attempting to extrapolate from bulk material behavior, requires the development of new measurement techniques. In particular, measurements of individual meso-or nanoscale objects can provide information about their structure which is unavailable by other means. In this report, we perform measurements of ion currents through a few hundred nanometer long MnO 2 rods deposited in single polymer pores. The recorded current confirms an existence of a meshlike character of the MnO 2 structure and probes the effective size of the mesh voids and the polarity of surface charges. The recorded ion current through deposited MnO 2 structure also suggests that the signal is mostly due to metal cations and not to protons. This is the first time that ionic current measurements have been used to characterize mesoporous structure of this important electrode material.

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

“…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.…”

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

“…Note that the ion current rectification observed in pores that were only partially filled with PMMA, is reminiscent of a previously reported rectifying system of the same type of cylindrical pores containing a porous MnO 2 rod. 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 Electrochemical Performance of Deposited Manganese Oxide-Based Film as Electrode Material for Electrochemical Capacitor Application

“…There are still many studies carried out to investigate other possible factors affecting the deposited manganese oxide-based film. For example, by studying the porosity of the manganese oxide-based film, one can also inspect more details about the structure and charge transport properties [94]. More and more deposition techniques have been developed and studied to prepare the manganese oxide-based film.…”