Sol-Gel Synthesis Using Novel Chelating Agent and Electrochemical Characterization of Binary Doped LiMn<sub>2</sub>O<sub>4</sub> Spinel as Cathode Material for Lithium Rechargeable Batteries

Abstract

LiMn 2 O 4 and LiCu x Cr y Mn 2−x−y O 4 (x = 0.50; y = 0.05-0.50) powders have been synthesized via solgel method for the first time using Myristic acid as chelating agent. The synthesized samples have been taken to physical and electrochemical characterization such as thermo gravimetric analysis (TG/DTA), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), field-emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM) and electrochemical characterization viz., electrochemical galvanostatic cycling studies, electrochemical impedance spectroscopy (EIS) and differential capacity curves (dQ/dE). XRD patterns of LiMn 2 O 4 and LiCu x Cr y Mn 2−x−y O 4 confirm high degree of crystallinity with good phase purity. FESEM image of undoped pristine spinel lucidly depicts cauliflower morphology with good agglomerated particle size of 50 nm while 0.5-Cu doped samples depict the pebbles morphology. TEM images of the spinel LiMn 2 O 4 and LiCu 0.5 Cr 0.05 Mn 1.45 O 4 authenticate that all the synthesized particles via sol-gel method are nano-sized (100 nm) with spherical surface and cloudy particles morphology. The LiMn 2 O 4 samples calcined at 850˚C deliver the high discharge capacity of 130 mA•h/g with cathodic efficiency of 88% corresponds to 94% columbic efficiency in the first cycle. Among all four compositions studied, LiCu 0.5 Cr 0.05 Mn 1.45 O 4 delivers 124 mA•h/g during the first cycle and shows stable performance with a low capacity fade of 1.1 mA•h/g cycle over the investigated 10 cycles.

Enhancing Lithium Manganese Oxide Electrochemical Behavior by Doping and Surface Modifications

“…More aspects related to LiNi 0.5 Mn 1.5 O 4 will be discussed in other sections of the review (see Future prospects). Strategies employed for enhancing structural stability of the lithium manganese oxide spinel included cation multi doping [71][72][73][74][75][76].…”