Lithium-ion transfer at LiMn2O4 thin film electrode prepared by pulsed laser deposition
2003; Elsevier BV; Volume: 5; Issue: 6 Linguagem: Inglês
10.1016/s1388-2481(03)00113-9
ISSN1873-1902
AutoresIzumi Yamada, Takeshi Abe, Yasutoshi Iriyama, Zempachi Ogumi,
Tópico(s)Conducting polymers and applications
ResumoLiMn2O4 thin film electrode was prepared by pulsed laser deposition for fabrication of structurally ordered electrode/electrolyte interface. Li-ion transfer at the LiMn2O4 electrode was studied by AC impedance spectroscopy. At potentials below 3.70 V (vs. Li/Li+), no semi-circle was observed on Nyquist plot. No oxidation and reduction currents were observed in cyclic voltammogram of LiMn2O4 thin film electrode at the potential range of 3.50–3.70 V, showing blocking electrode behaviors. Nyquist plots gave one semi-circle in the higher frequency region and a linear Warburg impedance in the lower frequency region at potential region above 3.80 V. The resistance of semi-circle was dependent on electrode potential and practical electrical resistance of LiMn2O4 along the thickness was negligible because of its small thickness. Hence, the semi-circle was identified as resistance for interfacial lithium-ion transfer. The resistance decreased with increasing electrode potentials up to 4.0 V and then increased with increasing electrode potentials. Temperature dependency of the resistance gave activation energy of 50 ± 2.4 kJ mol−1, indicating that high activation barrier exists at electrode/electrolyte interface for lithium-ion transfer.
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