Microstructure of the LiCoO 2 (cathode)/La 2/3- xLi 3 xTiO 3 (electrolyte) interface and its influences on the electrochemical properties
Abstract
Two different types of lithium lanthanum titanate (LLT)/LiCoO 2 assemblies were produced by depositing the LiCoO 2 cathode on the cleaved or polished surfaces of polycrystalline LLT to investigate the effects of the LLT/LiCoO 2 interface structure on the electrochemical properties of the assemblies. The microstructures and electrochemical properties of the assemblies were investigated as a function of charge/discharge cycle number. Cyclic voltammetry indicates that anodic and cathodic peaks shift to higher and lower potentials, respectively, with cycle number for the assembly produced with the cleaved LLT, whereas these potential changes are negligibly small for that produced with the mechanically polished LLT. LiCoO 2 is formed epitaxially on LLT with the orientation relationships (1 1 0) LLT// (1 1 2 bar 0)LiCoO2 and [0 0 1] LLT// [ 4 bar 4 0 1 ]LiCoO2 for both assemblies, but amorphous regions are formed at the interface for the assembly produced with polished LLT. The amorphous region is considered to play an important role in the cycle stability of the assembly upon charging/discharging.
- Publication:
-
Acta Materialia
- Pub Date:
- 2007
- DOI:
- 10.1016/j.actamat.2007.04.031
- Bibcode:
- 2007AcMat..55.4713K
- Keywords:
-
- Crystalline oxides;
- Interface structure;
- Interface defects;
- Transmission electron microscopy (TEM);
- Electrochemistry