Li-Mn-O Thin Film Cathode prepared at Room Temperature Thin Film & Battery Materials Lab. National...
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Li-Mn-O Thin Film Cathode prepared Li-Mn-O Thin Film Cathode prepared at Room Temperature at Room Temperature Thin Film & Battery Materials Lab. National Research Lab. Kangwon Nat’l Univ. Jeong-Kyu Lim a , Hyeon-Young Lee a , Serk-Won Jang a , Seung -Joo Lee b and Sung-Man Lee a a Department of Advanced Material Science and Engineering, Kangwon National University, Chunche on, Kangwondo, 200-701, South Korea b Microsystem Center, Korea Institute of Science a nd Technology, Seoul, South Korea
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Transcript of Li-Mn-O Thin Film Cathode prepared at Room Temperature Thin Film & Battery Materials Lab. National...
Li-Mn-O Thin Film Cathode preparedLi-Mn-O Thin Film Cathode preparedat Room Temperature at Room Temperature
Thin Film & Battery Materials Lab.National Research Lab.
Kangwon Nat’l Univ.
Jeong-Kyu Lima, Hyeon-Young Leea, Serk-Won Janga, Seung -Joo Leeb and Sung-Man Leea
a Department of Advanced Material Science and Engineering, Kangwon National University, Chuncheon, Kang
wondo, 200-701, South Korea
b Microsystem Center, Korea Institute of Science and Technology, Seoul, South Korea
Introduction Introduction
Thin Film & Battery Materials Lab.National Research Lab.
Kangwon Nat’l Univ.
LiMn2O4 spinel and related compounds Of great interest for use as cathodes in rechargeable lithium batteries.
Crystalline thin-film lithium manganese oxide cathodes Fabricated by physical vapor deposition followed by a high-temperature annealing.
The fabrication of the thin-film cathodes without post-annealing at high temperatures Useful for extensive applications of thin film lithium batteries.
The preparation and electrochemical characterization of thin-film lithium manganese oxide cathodes by r.f. sputtering from LiMn2O4 and LiMnO2 targets at room temperature.
In this work
Experimental procedureExperimental procedure
- 2 inch disk type - Pressing : cold pressing or hot pressing - Sintering : 950 for 12hr in air℃
Target preparation
- RF power : 30~75 W - Substrate : SUS (0.3t, Φ12) - film thickness : 0.5 to 2 ㎛ - Ar/O2 mixture : from 10/1 to 20/1 (5 mTorr)
Thin film fabrication
- XRD (X-ray diffractometer) - α-step (Thickness profiler) - FE-SEM ( Field Emission – Scanning Electron Microscope )
Structural & Mechanical analysis - CR2016 Coin Cells - Anode : Li foil - Electrolyte : 1M LiPF6 dissolved in EC/DEC 1M LiClO4 dissolved in PC - cut-off voltage : 2.0 - 4.5V (5~50 ㎂ / ㎠ ) 2.3 - 4.3V
Electrochemical analysis
Thin Film & Battery Materials Lab.National Research Lab.
Kangwon Nat’l Univ.
Structure AnalysisStructure Analysis
Thin Film & Battery Materials Lab.National Research Lab.
Kangwon Nat’l Univ.
Deposited thin film amorphous or nanao-crystalline
X-Ray Diffraction X-Ray Diffraction
10 20 30 40 50 60 70 80
As-deposited thin film
substrate : ( )
Target
Inte
nsi
ty (
a.u
.)
Diffraction angle (2)
10 20 30 40 50 60 70 80
as-deposited film
Target
substrate : ( )
Inte
nsi
ty (
a.u
.)Diffraction angle (2)
a. LiMna. LiMn22OO44 b. LiMnOb. LiMnO22
Charge/Discharge curve : LiMnCharge/Discharge curve : LiMn22OO44
Thin Film & Battery Materials Lab.National Research Lab.
Kangwon Nat’l Univ.
Cell test condition a. cutoff Voltage : 2.0-4.5V b. current density : 20㎂ c. Electrolyte : 1M LiPF6 +EC/DEC(1/1, v/v)
0 20 40 60 80
2.0
2.5
3.0
3.5
4.0
4.5
1 cycle 10 cycle 20 cycle 50 cycle
Capacity ( /cm2.m )
Vo
ltag
e (
V )
Charge/Discharge curve : LiMnOCharge/Discharge curve : LiMnO22
Thin Film & Battery Materials Lab.National Research Lab.
Kangwon Nat’l Univ.
Cell test condition a. cutoff Voltage : 2.5-4.3V b. current density : 30㎂ c. Electrolyte : 1M LiPF6 +EC/DEC(1/1, v/v)
a. as-depositeda. as-deposited b. post-annealing (200 )℃b. post-annealing (200 )℃
0 10 20 30 40
2.5
3.0
3.5
4.0
4.5
LiMnO2
1st 10th 20th
Capacity ( h/cm2.m )
Vo
ltag
e (
V )
0 10 20 30 40 50
2.5
3.0
3.5
4.0
4.5
LiMnO2-Post annealing
1st 10th 20th
Capacity ( h/cm2.m )
Vo
ltag
e (
V )
Thin Film & Battery Materials Lab.
National Research Lab. Kangwon Nat’l Univ.
20 ㎂
50 ㎂
Capacity vs cycle number : LiMnCapacity vs cycle number : LiMn22OO44
0 10 20 30 40 500
20
40
60
80
Cap
acit
y (
Ah
/cm
2 .m)
Cycle Number
10 ㎂Cell test condition a. cutoff Voltage : 2.0-4.5V b. current density : 10, 20, 50㎂ c. Electrolyte : 1M LiPF6 +EC/DEC(1/1, v/v)
Thin Film & Battery Materials Lab.
National Research Lab. Kangwon Nat’l Univ.
Capacity vs cycle number : LiMnOCapacity vs cycle number : LiMnO22
Cell test condition a. cutoff Voltage : 2.5-4.3V b. current density : 30㎂ c. Electrolyte : 1M LiPF6 +EC/DEC(1/1, v/v)
0 5 10 15 20
0
10
20
30
40
50
As-deposited Post-annealing
Cap
acit
y (
h/c
m2 .m
)
Cycle Number
Thin Film & Battery Materials Lab.
National Research Lab. Kangwon Nat’l Univ.
Rate-capability : LiMnRate-capability : LiMn22OO44
0
20
40
60
80
100
10 20 505
Current density()
2nd cycle
No
rmal
ized
Cap
acit
y (%
)
Normalized capacity = at 2nd cycleQ
Qi
i = 5㎂
Conclusion Conclusion
Thin Film & Battery Materials Lab.National Research Lab.
Kangwon Nat’l Univ.
Thin film electrodes produced by r.f. sputtering from an LiMn2O4 target showed reasonable electrochemical properties as a cathode for thin film rechargeable lithium batteries.
Thin films deposited from a LiMnO2 target exhibits a poor cyclability, which is significantly improved by post-annealing at 200℃
