Sonochemical synthesis of mesoporous MnO2 for Zinc-Air battery applications

MnO2 is one of the candidate materials for the application to electrochemical capacitors, Li-ionbatteries, sensors and catalysts [1]. In energy-storage devices, nano structured MnO2 has beenused as an active material because of its low cost and natural abundance as well as it beingenvironmentally safe [2]. Sonochemical technique has proved to be useful method forgenerating nano structures of oxide materials with highly pure and unusual properties in shortreaction times [3].Here in, nanostructured MnO2 was synthesized using a simple one-step sonochemical methodin the presence of poly (ethylene glycol)-block poly (propylene glycol)-block-poly (ethyleneglycol) (P123) as a soft template as well as a reducing agent. Prepared samples have beencharacterized using X-ray diffraction (XRD), morphology of the samples has beencharacterized by field-emission scanning electron microscopy (FESEM). The pore structures ofthe prepared samples were tested by N2 adsorption-desorption measurements. The activity andstability of this catalyst was evaluated by preparing air electrodes with primary Zinc−Airbatteries that consume ambient air.The XRD results indicated that MnO2 sample was poorly crystalline. The FESEM imagesshowed that the nanostructure of MnO2 was composed. The size of nanoparticles were about10-13 nm. A BET surface area of 87 m2/g is achieved for mesoporous MnO2 sample. Theresults of electrochemical tests revealed that the peak power density of Zinc-Air batteries were136.05 mW/cm2. The cells galvanostatic discharge showed maximum discharge current densityof 200 mA/cm2.

Keywords:

MnO2 nanostructure , Sonochemical synthesis , Zinc-Air battery