ENHANCED SUPERCAPACITIVE PERFORMANCE OF NANOCRYSTALLINE Mn3O4 SYNTHESIZED BY HYDROTHERMAL METHOD

Abstract

Mn₃O₄ nanoparticles have been successfully synthesized by a simple hydrothermal method at low temperatures. The processing conditions such as reaction temperature and time were optimized to synthesized phase pure nanocrystalline Mn₃O₄ with good electrochemical properties. The particles synthesized at a reaction temperature of 150°C for 12 h exhibited different characteristic peaks along with (211) predominant orientation which corresponds to tetragonal structure of Mn₃O₄ with space group I4₁/amd (141) and estimated crystallite size of 32 nm. The SEM analysis reveals that the octahedral shape of grains with an average grain size of 180 nm. The vibrational studies from Raman and FTIR measurements confirmed the microstructure and presence of Mn-O bonding. The conductivity of the product was increased with increasing temperature following the Arrhenius behavior with estimated activation energy of 0.37 eV. The supercapacitive performance of nanocrystalline Mn₃O₄ octahedrons in 1M Na₂SO₄ aqueous electrolyte exhibited a high specific capacitance of 348 Fg^-1 at current density of 0.5 mAcm^-2 and 70% capacitive retention even after 4000 cycles.