TY  - JOUR
AU  - Dellen, Christian
AU  - Gehrke, Hans-Gregor
AU  - Möller, Sören
AU  - Tsai, Chih-Long
AU  - Breuer, Uwe
AU  - Uhlenbruck, Sven
AU  - Guillon, Olivier
AU  - Finsterbusch, Martin
AU  - Bram, Martin
TI  - Time-of-flight secondary ion mass spectrometry study of lithium intercalation process in LiCoO$_2$ thin film
JO  - Journal of power sources
VL  - 321
SN  - 0378-7753
CY  - New York, NY [u.a.]
PB  - Elsevier
M1  - FZJ-2016-02540
SP  - 241-247
PY  - 2016
AB  - A detailed time-of-flight secondary ion mass spectrometry (ToF-SIMS) analysis of the lithium de-/intercalation in thin films of the insertion cathode material lithium cobalt oxide is presented. The LiCoO2 (LCO) thin films are deposited by radio frequency magnetron sputtering at 600 °C, having a (003) preferred orientation after the deposition. The thin electrode films are cycled with liquid electrolyte against lithium metal, showing 80-86% extractable capacities. After disassembling the cells, the depth resolved elemental distribution in the LCO is investigated by ToF-SIMS and glow discharge optical emission spectroscopy. Both techniques show a stepwise lithium distribution in charged state, leading to a lithium depleted layer close to the surface. In combination with the electrochemical results, the qualitative comparison of the different lithium depth profiles yields a reversible lithium extraction in the depleted area below the stability limit for bulk materials of LCO. For bulk LCO, a phase change normally occurs when the lithium concentration in LixCoO2 is lower than x=0.5. As a possible cause for the inhibition of the phase change, the preferred orientation and thus pinning of the crystal structure of the film by the substrate is proposed.
LB  - PUB:(DE-HGF)16
UR  - <Go to ISI:>//WOS:000377729200027
DO  - DOI:10.1016/j.jpowsour.2016.04.084
UR  - https://juser.fz-juelich.de/record/809434
ER  -