Surface modification of LiMn$_{\mathrm{2-x}}$Fe$_{\mathrm{x}}$O$_{\mathrm{4}}$ cathode materials with ZnO

We have successfully optimized the conditions for the synthesis of LiMn$_{\mathrm{2-x}}$Fe$_{\mathrm{x}}$O$_{\mathrm{4}}$ cathode materials for Li ion rechargeable batteries. We obtained the optimum calcinations temperatures for LiMn$_{\mathrm{2}}$O$_{\mathrm{4}}$, LiMn$_{\mathrm{1.75}}$Fe$_{\mathrm{0.25}}$O$_{\mathrm{4}}$, and LiMn$_{\mathrm{1.5}}$Fe$_{\mathrm{0.5}}$O$_{\mathrm{4}}$ as 850$^{\mathrm{o}}$C, 750$^{\mathrm{o}}$C, and 750$^{\mathrm{o}}$C, respectively. It has been reported in the literature that cycleability of LiMn$_{\mathrm{2}}$O$_{\mathrm{4\thinspace }}$cathode materials can be improved by surface modification of LiMn$_{\mathrm{2}}$O$_{\mathrm{4\thinspace }}$cathode materials with ZnO. In the present studies we have coated LiMn$_{\mathrm{2-x}}$Fe$_{\mathrm{x}}$O$_{\mathrm{4}}$ cathode materials with 2{\%} ZnO. The coating of ZnO onto LiMn$_{\mathrm{2-x}}$Fe$_{\mathrm{x}}$O$_{\mathrm{4\thinspace }}$were performed using zinc acetate as precursor materials. Appropriate quantity of zinc acetate was first dissolved in ethanol. Upon complete dissolution of zinc acetate in ethanol, required quantity of LiMn$_{\mathrm{2-x}}$Fe$_{\mathrm{x}}$O$_{\mathrm{4}}$ cathode material was poured in this solution, followed by continuous stirring for 4 hrs. The solution was then dried in an oven in air atmosphere. The physical characterization of the ZnO coated LiMn$_{\mathrm{2-x}}$Fe$_{\mathrm{x}}$O$_{\mathrm{4}}$ cathode materials were carried out using X-ray diffraction, differential scanning calorimetry (DSC) and thermo-gravimetric analysis (TGA). The detailed results of our investigation will be presented during the meeting.