The beneficial effect of reducing agent on the synthesis of manganese oxide nanowires as electrode materials for supercapacitors

Abstract

We examine the effects of precursor concentration and changes in the volume of reducing agent on the physico-chemical properties and electrochemical performance of the manganese oxide materials. Despite the fact that studies have been published on the usage of ethylene glycol as a reducing agent in the preparation of manganese oxide, there is no report on the investigation of the change in concentration of the precursor and volume of the reducing agent and how it impacts the physical, chemical, and electrochemical properties of the end products. Hence, the present work attempts to attain knowledge of the found research gap. Three different concentrations of precursor, viz. 0.1, 0.25, and 0.5 M, and four different volumes of reducing agent, viz. 0.5, 1, 3, and 5 ml, are studied. Crystallinity, morphology, chemical state, and surface area characteristics of the prepared samples are thoroughly studied using a variety of techniques. There is an increment in crystallinity and a significant change in morphology observed from nanowires to agglomerated nanostructures when the volume of reducing agent linearly increases. Interestingly, the results indicate that a lower volume of reducing agent can facilitate the development of an end product with optimum electrochemical properties for supercapacitor applications. The samples prepared with a minimum volume of reducing agent achieve a high specific surface area of 241 m2/g with a noteworthy specific capacitance of 179 F/g and also show an acceptable capacitance retention of 74.2% even after 5000 consecutive cycles. These findings might develop a favorable impact and understanding on the ratio of reactants that can be utilized in various material preparations.