Nano-sized MnO2particles produced by spray pyrolysis for a Zn/MnO2primary cell: comparative discharge performance studies with their bulk counterparts

Abstract

In this work, nano-sized spherical MnO2 particles with large surface area were synthesized employing spray pyrolysis for application in a Zn/MnO2 primary cell. Furthermore, we experimentally investigated the performance of nano-sized MnO2 particles when mixed with conductive additives, such as graphite and Vulcan carbon. The effect of particle size on the discharge performance of cells using two electrolytes (ZnCl2 and Zn(O2CCH3)2) was examined. To determine the crystalline phase, we comprehensively characterized microstructure, purity, particle size, thermal stability and surface area of both bulk and nano-sized particles. The measurements of electrochemical discharge characteristics, such as constant current discharge, cell capacity and internal resistance, were performed. From these discharge measurements, the nano-sized particle-based cathode (nano-sized MnO2/Vulcan carbon) discharge capacity was found to be 303 mA h g−1, which is 128% higher than the maximum value of the bulk MnO2 counterpart-based cathodes (bulk MnO2/Vulcan carbon). In addition, the internal resistance of the nano-sized MnO2/Vulcan carbon cathode-based cell appeared to be very low compared to that of all other bulk cathodes. Our results show that the configuration of nanoparticle-based cathode cells allows them to exhibit superior discharge capacity retention and increased shelf life compared to the conventional Zn/MnO2 cathode cells.