Elastic/anelastic behaviour during the phase transition in spinel LiMn₂O₄

Abstract

Both the Young`s modulus sound velocity (VE) and the internal friction (Q-1) have been measured for a polycrystalline sample of LiMn2O4 in the temperature range between 35 and 350 K, using a vibrating-reed technique. The resonance frequency (fr) employed for the measurement ranged from 0.81 kHz to 2.69 kHz at 300 K. At fr(300 K)=0.81 kHz, as temperature is lowered from 350 K, VE decreases down to 225 K (TA) Then, VE increases rapidly but monotonically with lowering temperature, though the magnitude of the slope (-dVE/dT) reduces. The overall increase in the velocity between TA and 100 K is about 68%. In the Q-1-versus-T curve, a large peak is clearly observed at around 210 K, as is the forming of a large shoulder on the low-temperature side; additionally, there exists a small Q-1 peak at around 120 K, though VE indicates no significant change at around 120 K. Furthermore, both the VE-versus-T curve and the Q-1-versus-T curve shift toward the higher-temperature side, by ~45 K and ~25 K, as fr(300 K) is increased from 1.32 kHz to 2.69 kHz. The observed elastic anomalies suggest that a phase transition occurs at temperatures below 290 K. This phase transition is probably due to an ordering of Mn3+ and Mn4+ ions on the octahedral 16d site in the spinel lattice. On the other hand, the origin of the Q-1 peak is considered to lie in a stress-induced relaxation of the distributions of Mn ions or Li ions.

Electric and Magnetic Properties of LiMn2O4- and Li2MnO3-Type Oxides

“…5b) follows analogous conductivity features in the same temperature range (Fig. 5a), corresponding to the presence of a structural transition already observed (10,26). This transition was attributed to the Jahn-Teller effect on the octahedral coordination of the Mn> ions.…”

Evolution of Solid Electrolyte Interphase during Cycling and Its Effect on Electrochemical Properties of LiMn2O4

“…The nano-indentation experiments on the LiMn 2 O 4 thin-film surface before the cycling tests, repeated 100 times at random locations with the same interval, indicated that the average elastic modulus of the pristine LiMn 2 O 4 was 13.5 GPa, with a standard deviation of 3.1 GPa. This is comparable to the elastic modulus of LiMn 2 O 4 reported by Sugiyama et al 24 The SEI thickness, measured by the nano-indentation technique using an AFM, showed a broad distribution and its range increased with an increasing number of cycles. The histogram of SEI thickness as a function of cycle number, shown in Fig.…”

Evidence of a Cationic Substitution Domain in Lithium-Manganese Spinels

“…Some controversy exists in the literature [2,[7][8][9] on the magnetic susceptibility of the stoichiometric LiMn 2 0 4 which shows a sample dependent behaviour, particularly at low temperature. The spread of results may arise from differences in the preparation methods, which can easily introduce unwanted spurious phases [10].…”