Power and capacity fade mechanism of LiNi0.8Co0.15Al0.0502composite cathodes in high-power lithium-ion batteries
High-power Li-ion cells that were tested at elevatedtemperatures showed a significant impedance rise, which was associatedprimarily with the LiNi0.8Co0.15Al0.05O2 cathode. By systematicallycollecting thousands of Raman spectra from 50 x 80 mm areas at 0.9 mmspatial resolution, and integrating the respective bands of the cathodecomponents for each spectrum, we were able to produce color-coded,semi-quantitative composition maps of cathode surfaces. Raman microscopyimages of cathodes from tested cells revealed that cell cycling orstorage at elevated temperatures led to significant changes in theLiNi0.8Co0.15Al0.05O2/elemental-carbon surface concentration ratio. Theloss of conductive carbon correlated with the power and capacity fade ofthe tested cathodes. The cathode surface state of charge (SOC) variedbetween individual grains of active material, and at some locations thespectra indicated the presence of fully charged material, despite thedeep cell discharge at the end of testing.
- Research Organization:
- Ernest Orlando Lawrence Berkeley NationalLaboratory, Berkeley, CA (US)
- Sponsoring Organization:
- USDOE. Assistant Secretary for Energy Efficiency andRenewable Energy. Office of the FreedomCAR and Vehicle TechnologiesProgram
- DOE Contract Number:
- AC02-05CH11231
- OSTI ID:
- 894557
- Report Number(s):
- LBNL--54273; BnR: VT0301030
- Country of Publication:
- United States
- Language:
- English
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