High-Voltage Performance of Ni-Rich NCA Cathodes: Linking Operating Voltage with Cathode Degradation
- Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
- Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Univ. of Tennessee, Knoxville, TN (United States)
High-voltage Ni-rich cathodes have been studied as a possible way to achieve high energy density in Li-ion batteries. However, capacity fade due to structural changes at high voltages has limited their applications. In this study, we identify 4.5 V (vs. graphite) as the optimum upper cutoff voltage (UCV) for a Ni-rich NCA cathode [LiNi0.8Co0.15Al0.05O2]. At this UCV, NCA delivers a 12 % increase in reversible capacity (when discharged to 2.5 V) and retains 92 % of its initial capacity after 100 cycles at 1C/-1C cycling when compared to 4.2 V as UCV. By increasing UCV to 4.7 V, the discharge capacity can be raised to >200 mAh/g. However, the rate of capacity fade is greater when compared to 4.5 V as UCV. This increased rate of capacity fade, at higher UCV, is related to irreversible lattice contractions that leads to structural rearrangement at charged states during high-voltage cycling. Lastly, our results show a change in transition metal oxidation states and an onset of structural ordering occurs when the UCV is 4.7 V.
- Research Organization:
- Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States)
- Sponsoring Organization:
- USDOE Office of Energy Efficiency and Renewable Energy (EERE), Vehicle Technologies Office (EE-3V); USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22). Materials Sciences & Engineering Division; USDOE Office of Science (SC), Basic Energy Sciences (BES). Scientific User Facilities Division
- Grant/Contract Number:
- AC05-00OR22725
- OSTI ID:
- 1561675
- Alternate ID(s):
- OSTI ID: 1558680
- Journal Information:
- ChemElectroChem, Vol. 6, Issue 22; ISSN 2196-0216
- Publisher:
- ChemPubSoc EuropeCopyright Statement
- Country of Publication:
- United States
- Language:
- English
Web of Science
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