Abstract
We present in this paper a modification and stabilization approach for the surface of a high specific capacity Ni-rich cathode material LiNi0.85Co0.10Mn0.05O2 (NCM85) via SO2 gas treatment at 250-400 °C, in order to enhance its electrochemical performance in advanced lithium-ion batteries. It was established that SO2 interactions with NCM85 result in the formation of a nanometer-sized Li2SO4 surface layer on the oxide particles with no impact on the bulk structure of the material and its morphology. We consider the above interactions as oxidation-reduction processes resulting in direct oxidation of sulfur and partial reduction of Ni3+ as revealed by high-resolution XPS and electron paramagnetic resonance studies. The important impacts of the SO2 treatment are a remarkably stable cycling performance of cathodes comprising this material with ∼10% increase in capacity retention and lesser voltage hysteresis upon cycling compared to untreated NCM85 cathodes. The SO2-treated NCM85 material is also significantly thermally stable, demonstrating lower heat evolution upon thermal reactions with standard EC-EMC/LiPF6 solutions by 12-20%, compared to untreated material. The proposed approach to modify the surface of Ni-rich NCM cathode materials by SO2 treatment is demonstrated to be a promising method to enhance their electrochemical performance. This work demonstrates a leap in performance of Ni-rich NCM cathode materials by increasing the content of nickel compared to any benchmark cathodes and is a promising approach for stabilization by surface modification.
Original language | English |
---|---|
Pages (from-to) | 3609-3618 |
Number of pages | 10 |
Journal | ACS Applied Energy Materials |
Volume | 3 |
Issue number | 4 |
DOIs | |
State | Published - 27 Apr 2020 |
Keywords
- Li-ion batteries
- Ni-rich NCM cathode materials
- electrochemical performance
- surface treatment with SOgas
- thermal behavior
ASJC Scopus subject areas
- Chemical Engineering (miscellaneous)
- Energy Engineering and Power Technology
- Electrochemistry
- Materials Chemistry
- Electrical and Electronic Engineering