In:
Materials Advances, Royal Society of Chemistry (RSC), Vol. 4, No. 17 ( 2023), p. 3746-3758
Kurzfassung:
High energy density Li-rich 0.33Li 2 MnO 3 ·0.67LiNi 0.4 Co 0.2 Mn 0.4 O 2 (HE-NCM) layered structure cathodes for Li-ion batteries provide higher capacity gain via incorporation of an excess of lithium into the host. As a serious drawback, these cathodes suffer from continuous voltage fade upon cycling. Recently, high capacity retention, rate capability and low voltage hysteresis were achieved for HE-NCM by new thermal double gases SO 2 and NH 3 treatment. However, so far a fundamental understanding of the mechanisms responsible for this improved stability is missing. Herein, a comprehensive study of the chemical composition and electronic structure modifications of a series of HE-NCM (untreated, treated, carbon- and binder- free) is performed using advanced electron spectroscopy techniques supported by theoretical calculations. We demonstrate that the double gases treatment process leads to a partial reduction of Co 3+ and Mn 4+ . The suggested chemical reactions include electron transfer from SO 2 , which behaves as a Lewis acid, to the transition metal sites accompanied by decomposition of SO 2 and a characteristic surface modification which acts as protective layer for the HE-NCM.
Materialart:
Online-Ressource
ISSN:
2633-5409
Sprache:
Englisch
Verlag:
Royal Society of Chemistry (RSC)
Publikationsdatum:
2023
ZDB Id:
3031236-X
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