Structural Origin of Suppressed Voltage Decay in Single-Crystalline Li-Rich Layered Li[Li0.2 Ni0.2 Mn0.6 ]O2 Cathodes.
Small
; 18(25): e2201522, 2022 Jun.
Article
em En
| MEDLINE
| ID: mdl-35607746
ABSTRACT
Lithium- and manganese-rich layered oxides (LMLOs, ≥ 250 mAh g-1 ) with polycrystalline morphology always suffer from severe voltage decay upon cycling because of the anisotropic lattice strain and oxygen release induced chemo-mechanical breakdown. Herein, a Co-free single-crystalline LMLO, that is, Li[Li0.2 Ni0.2 Mn0.6 ]O2 (LLNMO-SC), is prepared via a Li+ /Na+ ion-exchange reaction. In situ synchrotron-based X-ray diffraction (sXRD) results demonstrate that relatively small changes in lattice parameters and reduced average micro-strain are observed in LLNMO-SC compared to its polycrystalline counterpart (LLNMO-PC) during the charge-discharge process. Specifically, the as-synthesized LLNMO-SC exhibits a unit cell volume change as low as 1.1% during electrochemical cycling. Such low strain characteristics ensure a stable framework for Li-ion insertion/extraction, which considerably enhances the structural stability of LLNMO during long-term cycling. Due to these peculiar benefits, the average discharge voltage of LLNMO-SC decreases by only ≈0.2 V after 100 cycles at 28 mA g-1 between 2.0 and 4.8 V, which is much lower than that of LLNMO-PC (≈0.5 V). Such a single-crystalline strategy offers a promising solution to constructing stable high-energy lithium-ion batteries (LIBs).
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Coleções:
01-internacional
Base de dados:
MEDLINE
Idioma:
En
Revista:
Small
Assunto da revista:
ENGENHARIA BIOMEDICA
Ano de publicação:
2022
Tipo de documento:
Article
País de afiliação:
China