Abstract:
In the traditional Duracell battery, the results obtained to date remain marginal in terms of cyclability. The development of the existing Zn-MnO2 with superior electrochemical performance for use in alkaline rechargeable batteries is reported. Electrolytic manganese dioxide (EMD) was synthesized from a conventional manganese sulphate bath but having a unique non-ionic surfactant (Pluronic F127), and activated carbon, in an electrolytic cell. The surface areas and morphologies of the as-prepared EMDs were influenced by the presence of these novel additives in the solution while the X-ray data revealed that there was no noticeable change in the crystal orientations thus all the EMDs were structurally similar. The synergistic effect of the optimal ratio of surfactant to carbon powder produced rod-like arrays exhibiting a larger surface area, which facilitates ion transport for better energy storage. It is interesting to note that EMD deposited in the presence of F127 showed better cyclability whereas in the presence of carbon, although it showed better storage capability, it was endowed with poor efficiency when compared with the surfactant added sample, nevertheless the results are better than the existing Zn-MnO2 technology (additive free EMD). Therefore, both the surfactant (50 mg dm(-3)) and the activated carbon (5 g dm(-3)) have been added together in the bath and the resultant EMD exhibits a high specific capacity and an excellent cycling stability. Moreover, the presence of surfactant and activated carbon improved the discharge capacity and its retention thus making this alkaline technology feasible for storing renewable energy for future use. The synergistic effect and the mechanism involved have been discussed.