Influence of Sm3+ ion in structural, morphological, and electrochemical properties of LiMn2O4 synthesized by microwave calcination

LiSmxMn2-xO4 samples were synthesized via co-precipitation technique. The structural properties of the synthesized materials were studied using X-ray diffraction analysis and it confirmed the cubic spinel structure for all the compounds. The lattice parameter of LiMn2O4 was observed to be 8.2347 C-0 and it decreased with Sm3+ concentration, due to the shrinkage in cell volume aided by higher binding energy between Sm-O bond. The SEM micrographs were analyzed using Image processing software (Image-J) to ascertain the pore and grain properties. The microwave synthesis had been observed to control the bulk grain formation and had yielded lesser porous and nanoparticles. The particle size distributions obtained through photocross correlation laser diffraction analysis had shown that LiMn2O4 with 60 nm and Sm-doped compounds with similar to 30 nm, respectively. The cyclic voltammetry studies had revealed the decrease in electrocatalytic behavior in the initial cycle for compounds doped with Sm3+ ion. The initial capacities of LiMn2O4, LiSm0.05Mn1.95O4 and LiSm0.10Mn1.90O4 substituted compounds were observed to be 134.87 mAhg(-1), 132.22 mAhg(-1) and 126.41 mAhg(-1), respectively. The cells were simulated using 1D model namely Dualfoil5.1 program. The simulated results coincide well with the measured results. The cycle life studies reveal 93% capacity retention of samarium-0.05-doped samples when compared with 78.4% of the LiMn2O4.