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The differential thermal analysis (DTA) curves were measured at different heating rates in flowing air for studying the synthesis of the spinel LiMn2O4 with Li2CO3 and MnO2. The reaction began at about 503K, and finished at about 873K. The apparent activation energy of Kissinger method was about 122.77kJ·mol-1, the reaction order was 1.67, the frequency factor was 7.81×10 9, and therefore the kinetic equation was d δd t= A·exp(-ERT)·(1-δ)n = 7.81×10 9 exp(-122770RT)·(1-δ)1.67. Coats-Redfern integral method was used to analyze the DTA curves of the samples at different heating rates, and the calculated apparent activation energy and frequency factor were 112.13kJ·mol-1 and 1.18×10 9, respectively, rather close to that of Kissinger method. X-ray diffraction (XRD) and scanning electron microscope (SEM) results shown that the synthesized LiMn2O4 possesses pure phase, regular shape and normal particle distribution.
The differential thermal analysis (DTA) curves were measured at different heating rates in flowing air for studying the synthesis of the spinel LiMn2O4 with Li2CO3 and MnO2. The reaction starts at about 503K, and finished at about 873 K. The apparent activation energy of Kissinger method was about 122.77 kJ · mol -1, the reaction order was 1.67, the frequency factor was 7.81 × 10 9, and therefore the kinetic equation was d δd t = A · exp (-ERT) · (1-δ) n = 7.81 × 10 9 exp (-122770RT) · (1-δ) 1.67. Coats-Redfern integral method was used to analyze the DTA curves of the samples at different heating rates, and the calculated apparent activation energy and frequency factor were 112.13 kJ · mol -1 and 1.18 × 10 9, respectively, rather close to that of Kissinger method. X-ray diffraction (XRD) and scanning electron microscope (SEM) results showed that synthesized LiMn2O4 possesses pure phase, regular shape and normal particle distribution.