Publication Date:
2016-09-20
Description:
Li-ion batteries have been recognized as promising devices for a sustainable society. Layered LiCoO 2 and graphite are commonly used as electrode materials for Li-ion batteries. When charging and discharging, Li-ions are extracted or inserted into the interlayers, which causes changes in volume. Scanning probe microscopy (SPM) can allow high resolution imaging of these volume changes, which enables us to investigate Li-ion migration without destruction. We observed volume changes in the LiCoO 2 cathode using SPM and successfully imaged the distribution of the volume changes corresponding to the LiCoO 2 particles. Volume changes in the interspace were significantly larger than those in the particles. The large volume changes are caused by electrolyte flux induced by changes in concentration of Li ions. The volume changes were greatly reduced when the electrolyte dried out. The dry-out and infiltration of electrolyte between the LiCoO 2 particles and the current collector spread out with the procedure of degradation of the batteries. The boundaries between the dry-out and infiltration regions acted as barriers of electrolyte flux.
Print ISSN:
0021-9606
Electronic ISSN:
1089-7690
Topics:
Chemistry and Pharmacology
,
Physics
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