Electrochemical and ex situ x-ray study of Li(Li{sub 0.2}Ni{sub 0.2}Mn{sub 0.6})O{sub 2} cathode material for Li secondary batteries.

Journal Article · Mon Sep 01 04:00:00 EDT 2003 · Electrochem. Solid State Lett.

DOI:https://doi.org/10.1149/1.1594411· OSTI ID:961270

Kang, S -H; Sun, Y K; Amine, K

Electrochemical properties of Li(Li{sub 0.2}Ni{sub 0.2}Mn{sub 0.6})O{sub 2}, synthesized by a sol-gel method, were studied by galvanostatic cycling. When the Li/Li(Li{sub 0.2}Ni{sub 0.2}Mn{sub 0.6})O{sub 2} cell was cycled at 2.0--4.6 V, the material showed a long, irreversible plateau at 4.5--4.6 V and exhibited very high initial charge capacity of 240 mAh/g, which is much larger than a theoretical value for the reaction of Li(Li{sup +}{sub 0.2}Ni{sup 2+}{sub 0.2}Mn{sup 4+}{sub 0.6})O{sub 2} {yields} Li{sub 0.6}(Li{sup +}{sub 0.2}Ni{sup 4+}{sub 0.2}Mn{sup 4+}{sub 0.6})O{sub 2} + 0.4Li (126 mAh/g). Discharge capacity of the material gradually increased from 155 at the first cycle to 205 mAh/g at the tenth cycle and was stabilized afterward. From the ex situ X-ray study, we found that Li ions in the transition metal layer were irreversibly extracted during charging at a voltage higher than 4.5 V; the diffraction peaks corresponding to Li in the transition metal layer were hardly observed in the cathode material after extended cycling. The Li/Li(Li{sub 0.2}Ni{sub 0.2}Mn{sub 0.6})O{sub 2} cell that was cycled at 2.0--4.3 V showed stable but very small capacity (69 mAh/g) and Li in the transition metal layer remained almost intact. When the cell was initially charged to 4.6 V and then cycled at 2.0--4.3 V, the cathode material showed higher capacity (114 mAh/g) than the one cycled at 2.0--4.3 V.

• Research Organization: Argonne National Laboratory (ANL)
• Sponsoring Organization: EE
• DOE Contract Number: AC02-06CH11357
• OSTI ID: 961270
• Report Number(s): ANL/CMT/JA-46010
• Journal Information: Electrochem. Solid State Lett., Journal Name: Electrochem. Solid State Lett. Journal Issue: 9 ; Sep. 2003 Vol. 6; ISSN 1099-0062
• Country of Publication: United States
• Language: ENGLISH

Related Subjects

25 ENERGY STORAGE
36 MATERIALS SCIENCE
CAPACITY
CATHODES
CHARGES
DIFFRACTION
ELECTRIC BATTERIES
ELECTRIC POTENTIAL
ELECTRODES
IONS
LAYERS
LITHIUM
LITHIUM COMPOUNDS
MANGANESE OXIDES
MATERIALS
NICKEL OXIDES
PEAKS
SOL-GEL PROCESS
TRANSITION ELEMENTS
X-RAY DIFFRACTION