INVESTIGATION ON THE CRYSTALLOGRAPHY AND MORPHOLOGY OF LITHIUM COBALT MANGANESE TETROXIDE SYNTHESISED AT LOW TEMPERATURE WITH VARIOUS LITHIUM PRECURSORS

Chee Wayne Tan; Zul Hilmi  Che Daud; Zainab  Asus; Mohd Hasbullah Idris; Izhari Izmi Mazali; Mohd Kameil Abdul Hamid

Chee Wayne Tan 1Faculty of Mechanical Engineering, Universiti Teknologi Malaysia, 81310 Johor Bahru, Johor, Malaysia
Zul Hilmi Che Daud Automotive Development Centre, Faculty of Mechanical Engineering, Universiti Teknologi Malaysia, 81310 Johor Bahru, Johor, Malaysia
Zainab Asus Automotive Development Centre, Faculty of Mechanical Engineering, Universiti Teknologi Malaysia, 81310 Johor Bahru, Johor, Malaysia
Mohd Hasbullah Idris 1Faculty of Mechanical Engineering, Universiti Teknologi Malaysia, 81310 Johor Bahru, Johor, Malaysia
Izhari Izmi Mazali Faculty of Mechanical Engineering, Universiti Teknologi Malaysia, 81310 Johor Bahru, Johor, Malaysia
Mohd Kameil Abdul Hamid Faculty of Mechanical Engineering, Universiti Teknologi Malaysia, 81310 Johor Bahru, Johor, Malaysia

Keywords: LiCoMnO4, Cathode, Sol-gel, Calcination, Crystallography

Abstract

Spinel structured lithium cobalt manganese tetroxide (LiCoMnO₄) which exhibit reduction potential ranging between 5.1 – 5.6 V (vs. Li⁰ | Li⁺) was identified to be one of the prospective cathode candidates for next generation lithium-ion electrochemical systems offering unprecedented voltage output. This article highlights the significance of lithium precursor towards the crystallography and morphology of lithium cobalt manganese tetroxide (LiCoMnO₄). LiCoMnO₄ cathode compounds in this research were synthesised via sol-gel reaction with stoichiometric ratio of Li:Co:Mn maintained at 1:1:1. The sol-gel formed were subsequently converted into xerogel before subjected to facile one-step low temperature calcination protocol at 600 ˚C. The source of lithium was derived from four distinctive precursors, namely lithium acetate dihydrate (LiCH₃COO⸳2H₂O), lithium carbonate (Li₂CO₃), lithium fluoride (LiF) and lithium hydroxide monohydrate (LiOH⸳H₂O) respectively. Co-existence of multiple phases were detected within the resultant compound synthesised with LiCH₃COO⸳2H₂O, Li₂CO₃ and LiOH⸳H₂O being used as lithium precursor. X-ray diffraction coupled with Rietveld refinement revealed that single phase LiCoMnO₄ compound was attained from the post-calcinated specimen synthesised with LiF being used as the source of lithium. The adoption of LiF as lithium precursor also resulted in the formation of LiCoMnO₄ compound with relatively homogenized grain size as observed from field emission scanning electron microscopy (FESEM).