Electrochemical cycling-induced spinel formation in high-charge-capacity orthorhombic LiMnO{sub 2}
Li{sub x}Mn{sub 2}O{sub 4} spinel normally undergoes a transformation from its cubic to tetragonal phase when x exceeds 1 due to a collective Jahn-Teller distortion, resulting in poor cyclability when both the 4 and 3 V intercalation plateaus are utilized. In this study, the authors show that this transformation is suppressed in spinels of composition up to x {approx} 2 obtained through the electrochemical cycling of orthorhombic LiMnO{sub 2}. X-ray diffraction, transmission electron microscopy, and high-resolution electron microscopy studies together show the cycling produces a cubic spinel containing partial tetrahedral cation site occupancy and a nanodomain structure (20 to 50 nm size) within parent single-crystalline oxide particles. This structure is responsible for the cycling stability of electrochemically produced spinel. The reversible capacity (272 mAh/g) and energy density (853 Wh/kg) achieved at a low charge-discharge rate (3.33 mA/g) in the present samples are the highest among crystalline LiMnO{sub 2} materials reported to date.
- Research Organization:
- Massachusetts Inst. of Tech., Cambridge, MA (US)
- Sponsoring Organization:
- US Department of Energy; National Science Foundation
- DOE Contract Number:
- AC07-94ID13223
- OSTI ID:
- 20003173
- Journal Information:
- Journal of the Electrochemical Society, Journal Name: Journal of the Electrochemical Society Journal Issue: 9 Vol. 146; ISSN JESOAN
- Country of Publication:
- United States
- Language:
- English
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