Manganese dioxide is a promising cathode material for Li-ion batteries because it is earth-abundant, inexpensive and non-toxic. However, its poor cyclability and rate capability currently limit its application. Its low stability upon charging and discharging is attributed to irreversible processes accompanying Li+ insertion and removal. For example, volume expansion, phase changes, manganese dissolution, and low ionic and electronic conductivity are assumed to have dramatic impacts in the chargeability.1 In spite of the importance of electrode stability in batteries, observations of MnO2 degradation mechanism upon charging/discharging are sparse. We have developed a method to synthesize and characterize MnO2 particles using polymeric membranes with micrometer-sized gold tubes spanning the membrane thickness.2 The gold microtubes allow for electrochemical deposition of the particles at the tube openings on one side of the membrane (Figure 1a), and oxidation/reduction of the manganese in lithium perchlorate (Figure 1b). The effects of the number of charging/discharging cycles on the capacity, ionic conductivity and structure of these particles were measured by X-ray photoelectron spectroscopy, scanning electron microscopy, cyclic voltammetry and current-voltage curve. We observed major structural changes and dissolution effects in water compared to organic solvents.

Synthesis, electrochemical and structural characterization of manganese oxide particles on gold microtubes for battery applications

2019 Spring National Meeting

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.