Technical Report報文Development of Novel Ni0.8Co0.2OOH0.43Li0.57 ･Lix/C (0 ≦ x ≦ 1) System Li-Ion Cells
Miki Yasutomi*
Toru Tabuchi*
Hideo Yasuda*
Masanori Yamachi**

Abstract
Li-ion has been doped into Ni0.8Co0.2OOH0.43Li0.57 positive electrode by chemical method using Li-naphthalene organic complex solution. The novel Li-ion system cell has been successfully confirmed to be realized
by the evaluation test of laminate-type single cell composed of positive electrode with Ni0.8Co0.2OOH0.43Li0.57·
Lix (0 ≦ x ≦ 1) synthesized by the above chemical method and negative electrode with graphite. ThisNi0.8Co0.2OOH0.43Li0.57· Lix / C laminate-type single cell showed a good cycleability of discharge capacity retention of 90% at 20th cycle, though its discharge capacity was 75 mAh g-1 on the mass basis of positive active
material as the first trial test. This system is regarded as the high theoretical capacity from 591 mAh g-1 (y = 1)
to 292 mAh g-1 (y = 0), when x equals 1 according to the following reaction mechanism : Ni0.8Co0.2OOH1-yLiy·Lix⇄ Ni0.8Co0.2OOH1-y + (x+y) Li + (x+y) e .
+-of NiOOH・Li by new chemical method with Li-naph-

1 Introduction

thalene complex solution.3,4) Li-ion has been doped

A world-wide effort has been made to find alter-

into Ni0.8Co0.2OOH0.43Li0.57 as one of precursors fornative positive active materials for LiCoO2, LiNiO2,

the derivative positive active materials of NiOOH

and LiMn2O4 and negative active materials for car-by the new chemical method. The Ni0.8Co0.2OOHbon in existing Li-ion cells to meet the strong de-0.43

mand of higher energy density for portable phones

sized active material doped with lithium has beenand electric vehicles.

The NiOOH with a large

investigated for its cycleability with the practicaltheoretical capacity of 292 mAh g has been consid-

cells under the condition of the starved electrolyte,ered to be a promising candidate of positive active

wherein x is 0 ≦ x ≦ 1. The novel Li-ion cell has

material for 3-volt-class lithium cells.

However,been found to be a 3-volt-class high-energy-density

this material was impossible to be used for the posi-

cell with good cycleability. In this report, we willtive electrode for Li-ion cells with carbon negative

discuss the performance of these new cells with

one because of no lithium source in the discharged

Ni0.8Co0.2OOH0.43Li0.57·Lix positive active materials

state. Recently, we have succeeded in the synthesis

together with the electrochemical reaction mecha--11,2)

Li0.57·Lix positive electrode using this synthe-

nism of charge and discharge process.
*Department-F, Corporate R & D Center**Corporate R & D Center© 2004 GS Yuasa Corporation, All rights reserved.

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GS Yuasa Technical Report

2004 年 12 月

第 1巻

第1号

4.02 Experimental

3.5+

The Ni0.8Co0.2OOH0.43Li0.57·Lix positive electrode

Potential / V vs. Li / Lishowing open-circuit potential of 2.5 V vs. Li / Li+
was prepared by immersing the electrode with themixture of Ni0.8Co0.2OOH0.43Li0.57 : acetylene black(AB) : poly-vinylidene-fluoride (PVDF) in the mass
ratios of 80 : 5 : 15 using Al foil as a current collector into the complex solution with 0.25 mol dm-3
naphthalene and saturated metallic Li in 1-methoxybutane solvent followed by washing it withdimethyl carbonate (DMC). The negative electrode3.02.5
2.0
1.5
1.0
0.5
0.00.01

was prepared with the mixture of graphite, styrene

0.1

110Immersion time / hbutadiene rubber (SBR), and carboxylic methyl
cellulose (CMC) using Cu current collector. The

Fig. 1 Change in the open-circuit potential of
Ni0.8Co0.2OOH0.43Li0.57 electrode with immersion time.
Counter and reference electrodes : Metallic Li.
Electrolyte : 1 mol dm-3 LiClO4 containing EC andDEC in the volume ratio of 1:1.

test laminate-type single cells were prepared withboth electrodes, polyethylene film separator, and a
mixture of 1 mol dm-3 LiClO4 containing ethylene
carbonate (EC) and diethyl carbonate (DEC) in thevolume ratio of 1:1 as an electrolyte. The test cells
were discharged to 1.4 V at current density of 0.25

600mA cm after charging at the same current density

Amount of electricity / mAh g -1-2

to 4.1 V.

3 Results and discussion
The change in open-circuit potential of electrode with Ni 0.8Co 0.2OOH 0.43Li 0.57 synthesized bychemical method with various immersion times isshown in Fig. 1. The open-circuit potential of thiselectrode is found to shift toward less noble. The

500
400
300
200
10000.01electricity charged of this electrode after charging is shown in Fig. 2. The electricity charged is0.1110Immersion time / hfound to be increased with immersion time, and theFig. 2 Change in the amount of charged electricity of Ni0.8Co0.2OOH0.43Li0.57 electrode with immersion
time.
Counter and reference electrodes : Metallic Li.
Electrolyte : 1 mol dm-3 LiClO4 containing EC andDEC in the volume ratio of 1:1.
Charge : 0.25 mA cm-2 to 4.1 V.

value is reached to be large capacity of 500 mAh g-1
beyond the corresponding to the theoretical capacity of 292 mAh g-1 based on one molar Li extraction. These results mean that Li-ion is doped into
Ni0.8Co0.2OOH0.43Li0.57 by chemical method using Linaphthalene organic complex solution.
The initial charge-discharge characteristics ofrepresentative Ni0.8Co0.2OOH 0.43Li0.57·Lix / C sys-tem Li-ion laminate-type cell are shown in Fig. 3.

voltage, though the large irreversible capacity isThe new Li-ion system cell shows the monotonous

still observed at the present time. The cycle perfor-

discharge curve with the 3-volt-class operation

mance of the new laminate-type test cell is shown33

GS Yuasa Technical Report

2004 年 12 月

Discharge capacity retention / %4.0

Voltage / V

3.0

2.0

1.00.0第 1巻第1号

1008060402000204060010080

5101520Cycle number / -Amount of electricity / mAh g -1

Fig. 3 Charge-discharge characteristics of laminate-type single cell with Ni0.8Co0.2OOH0.43Li0.57·Lix
positive electrode synthesized by chemical method.
Negative active material : graphite.
Electrolyte : 1 mol dm-3 LiClO4 containing EC andDEC in the volume ratio of 1:1.
Charge : 0.25 mA cm-2 to 4.1 V.
Discharge : 0.25 mA cm-2 to 1.4 V.
Amount of electricity : Mass base of positive activematerial.

Fig. 4 Cycle performance of laminate-type single
cell with Ni0.8Co0.2OOH0.43Li0.57·Lix positive electrodesynthesized by chemical method.
Negative active material : graphite.
Electrolyte : 1 mol dm-3 LiClO4 containing EC andDEC in the volume ratio of 1:1.
Charge : 0.25 mA cm-2 to 4.1 V.
Discharge : 0.25 mA cm-2 to 1.4 V.

organic complex solution. The novel Li-ion cell within Fig. 4. This cell shows good cycleability with thethis obtained positive active material and graphite

discharge capacity retention of 90% at 20th cycle.

negative active material has been evaluated using

The cycleability of this system is considered to be

the practical cell in the condition of starved electro-based on the starved electrolyte condition of lami-lyte. The results were summarized as follows.

nate-type single cell judging from the fact that the(1) The novel Li-ion system cell has been successfully

cycleability of NiOOH positive electrode derivative

confirmed by the experimental cells composed ofof Ni0.8Co0.2OOH0.43Li0.57 active material was very

positive electrode with Ni0.8Co0.2OOH0.43Li0.57·Lix

trochemical charge-discharge reaction mechanism

electrode with graphite.

poor in flooded condition of electrolyte.

2)

The elec-synthesized by chemical method and negativeof novel Li-ion system seems to be described by the(2) The Ni0.8Co0.2OOH0.43Li0.57·Lix / C laminate-type

following equation (1).

single cell showed a good cycleability with dis-This system is regarded as the high theoreticalcharge capacity retention of 90% at 20th cycle,

capacity from 591 mAh g (y = 1) to 292 mAh g (ythough its initial discharge capacity was 75= 0), when x equals 1.

mAh g-1 on the mass basis of positive active ma--1

Ni 0.8 Co 0.2 OOH 1-y Li y ·Li x+ (x+y) Li+ + (x+y) e--1

⇄Ni 0.8 Co 0.2 OOH 1-yterial as the first trial experiment.

･････ (1)(3) The Ni0.8Co0.2OOH1-yLiy·Lix electrode is regarded
as the high theoretical capacity from 591 mAhg-1 (x=1) to 292 mAh g-1 (x=0).

4 Conclusions
Li-ion has been doped into Ni0.8Co0.2OOH0.43Li0.57
by the new chemical method using Li-naphthalene34

GS Yuasa Technical Report

2004 年 12 月

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3) M. Kitano, T. Tabuchi, H. Yasuda, M. Yamachi, Y.

References

Matsuda, and Y. Imai, The 44th Battery Sympo-sium in Japan , p.292 (2003).

1) J. Maruta, H. Yasuda, Y. Fujita, and M. Yamachi,Electrochem. Soc. Proc., Vol. 97-18, 151 (1997).

4) M. Yasutomi, T. Tabuchi, H. Yasuda, M. Yamachi,2) H. Sasaki, H. Yasuda, and M. Yamachi, GS NewsY. Matsuda, and Y. Imai, GS News Technical Re-Technical Report , 60, 12 (2001).

port , 63, 13 (2003).

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