Structural, electrical and electrochemical studies on doubly doped LiMn^sub 2-x^(GdNi)^sub x^O^sub 4^ cathode materials for Li-ion batteries

Doubly doped LiMn2−x(GdNi)xO4 (x = 0, 0.01, 0.02, 0.03, 0.04 and 0.05) materials with spinel structure have been synthesized by sol-gel method. Powder X-ray diffraction results have confirmed the formation of cubic spinel structure. FE-SEM studies showed that cubic spinel structure remained unchanged with notably modified particle size in the range of 200–400 nm. Cyclic Voltammetry results showed enhancement in Li+ intercalation and de-intercalation through decrease in redox potentials as a function of doping. Electrochemical Impedance Spectroscopy (EIS) results show decreased charge transfer resistance with addition of Gd and Ni. Charge-discharge studies for LiMn1.98(GdNi)0.01O4 show 67.1 mAh/g discharge capacity over other doped derivatives and pristine LiMn2O4 (60.6 mAh/g) in aqueous Li2SO4 electrolyte.