Study On Preparation Of LiMn₂O₄ Film Electrode By Chemical Solution Deposition Method

Preparation of film electrode is the base of micro battery and grotesque battery. LiMn2O4 got great attention for the reason of safety, low heat treatment temperature and low cost. This paper mainly studied the factors that influence the preparation of LiMn2O4 film on stainless steel by chemical solution deposition method.Firstly, choose an appropriate solution system to make a steady solution, and then LiMn2O4 film precursor was prepared on stainless steel by spin coating method with the solution. Secondly, Factors that influence the qualities and properties of the thin film were discussed. Results showed that the factors include: solvent and concentration of LiMn204 precursor solution, spin-coating speed, heating speed, sintering temperature and time etc. In the end, techniques of sintering under vacuum conditions were studied. LiMn2O4 films made under these conditions showed good performances, so synthesizing LiMn2O4 film at low sintering temperatures was realized.Experiments revealed that the best precursor solution system was composed of lithium acetate, manganese acetate, acetic acid, 2-methoxyethanol, polyvinylpyrrolidone (PVP) and deionized water. Best concentration of ions is 1.5mol/L and dispersant PVP monomer 0.8mol/L.Spin-coating speed, which affected the quality of LiMn2O4 film greatly, was also studied. It demonstrated that smooth LiMn2O4 film without cracks could formed under 2000 rotates/min with the solution Cion=1.5mol/L, CPVP=0.8mol/L, what's more, fewest spin-coating times were needed at that speed.It showed that better crystal films could formed when sintered between 350~550℃for 3 hours. With the increasing of temperature and the extending of time, the diffraction apices became stronger and the crystal became bigger. The latter phenomenon was also observed when sintering temperature was higher than 600℃and time longer than 4 hours, also impurities, such as Mn2O3, Mn3O4 and LiCrO2, appeared which became severer as temperature increased and time extended.As for the electrical performance, results showed an increase of discharge capacity with the increase of sintering temperature or time, while this property increased first and then decreased when sintered in 350℃for 3 hours. The thin films sintered at 550℃for 3 hours had highest...