Investigation of apparent diffusion of Li ion in HT-LiCoO2 films fabricated by pulsed laser deposition method

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Author(s)

Detail(s)

Original languageEnglish
Pages (from-to)818-822
Journal / PublicationJinshu Xuebao/Acta Metallurgica Sinica
Volume43
Issue number8
Publication statusPublished - Aug 2007

Abstract

The structure of LiCoO2 films prepared with the pulsed laser deposition (PLD) method was characterized by XRD, Raman spectroscopy and SEM, and their electrochemical properties were evaluated with cyclic voltammetry (CV). Results showed that the LiCoO2 films deposited at 600°C have a well-crystallized columnar HT-LiCoO2 structure with the average grain size less than 100 nm and a strong[001] preferred orientation, while these films contain trace amount of CO3O4. CV tests indicated that the HT-LiCoO2 films have good electrochemical reversibility but only a pair of redox peaks near 3.9 V (vs Li) were observed in the cyclic voltammograms. Potentiostatic intermittent titration technique (PITT) measurements revealed that the lithium ion diffusion coefficient of the HT-LiCoO2 films can reach 10-8-10-9 cm2/s, 1-2 orders of magnitude faster than those prepared by other methods including R. F. magnetron sputtering and, in the voltage range between 3.85-3.95 V (vs Li) the diffusion coefficient was 1-2 orders of magnitude lower than other voltage ranges. The former should be ascribed to the grain refinement of PLD-deposited HT-LiCoO2 films and existence of many voids, while the later may be due to the hindrance arising from phase boundary movement.

Research Area(s)

  • Li ion diffusion, LiCoO2, Pulsed laser deposition, Thin film battery