G Dmytriv, V Pavlyuk, I Tarasiuk - Li-zn-{al sn} zintl phase alloys for the anode materials of lithium batteries - страница 1

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ВІСНИК ЛЬВІВ. УН-ТУ VISNYK LVIV UNIV.

Серія хім. 2007. Bun. 48. Ч. I. С. 172-178    Ser. Khim. 2007. No 48. Part I. P. 172-178

УДК 546.281

Li-Zn-{Al, Sn} ZINTL PHASE ALLOYS FOR THE ANODE MATERIALS OF LITHIUM BATTERIES

G. Dmytriv 1, V. Pavlyuk 1, I. Tarasiuk 1, H. Pauly 2, H. Ehrenberg 2, B. Marciniak 3, W. Prochwicz 3, G. Schroeder 4

1 Ivan Franko Lviv National University, Kyryla and Mefodia Str., 6, 79005 Lviv, Ukraine

2 Materials Science, Darmstadt University of Technology, Petersenstr., 23, D-64287 Darmstadt, Germany

3 Institute of Chemistry and Environment Protection, Jan Dlugosz University, Armii Krajowej Str., 13/15, 42200 Czestochowa, Poland

4 Uniwersytet im. A. Mickiewicza, Grunwaldzka Str., 6, 60780 Poznan, Poland

Alloys from homogeneity ranges of solid solution LiZnxAl1-x (x = 0-1) and ternary compound Li^5-L5Zn05-15Sn was investigated as anode materials of lithium batteries. All tested phases crystallized in the Zintl phase NaTl structure (space group Fd 3 m). Current sources with these anodes in dependence of cathode materials and composition of anode material characterized by voltage 1.5­3.12 V and energy density 60-240 W h/kg.

Key words: Zintl phase, anode materials, lithium batteries.

Lithium ion rechargeable batteries are used as the power supply of cellular phones and several other portable electrical devices at present, and demand appears to increase exponentially. The concern about energy sources in the near future, either for electric vehicles or for large.scale batteries for electricity power storage, has made lithium ion rechargeable battery development into a growth area, which has gained high momentum for its research activities. There are three directions of current research of materials for lithium batteries: anode materials, electrolytes, and cathode materials [1]

In old models of lithium batteries pure lithium was used as anode material: Li-SOCl2 Li-MnO2, Li-TiS2 and other systems [2, 3]. Carbon matrix with distributed inside lithium is used as the anode.active material in modern lithium ion batteries. In both this case problem of chemical activity of pure lithium exist. This problem can be solving by using lithium alloys which having better technical and energetic parameters.

The main objective of presented investigations is to design of advanced lithium alloys that are attractive construction materials for anodes in both disposable (primary) and rechargeable (secondary) batteries due to its high electrochemical potential combined with a low equivalent mass. The great roles among such alloys play NaTl-type Zintl phases, for example LiAl Zintl phase that was the first commercial product as an anode material [4]. The search of new materials is impossible without the investigation of the phase diagrams, crystal structure of the compounds and their properties.

© Dmytriv G., Pavlyuk V., Tarasiuk I. et al., 2007

Li-Zn-{Al, Sn} ZINTL PHASE ALLOYS ...

Alloys for the anode materials was prepared from the pure metals (content of main element not less than 99.99 at. % except lithium, content of lithium - 99.8 at. %). Preparation of alloys was carried out in arc furnace in argon atmosphere at pressure 1.01105 Pa. Alloys was kept in purified indifferent oil after melting.

For the testing of alloys powder patterns was used. X-ray diffraction patterns were collected on a STOE STADI P powder diffractometer (MoKa1 radiation, 0.02° step of scanning, 8 sec/step for the 26? range 8-50°) or DRON-2.0 powder diffractometer (FeKa] radiation, 2°/min speed of scanning for the 26range 20-90°). The unit cell parameters were refined using the program LATCON [5]. The software package Fullprof was used for Rietveld refinements [6].

Electrochemical investigations was carried out in the real button-types current sources with electrode square 1.65 sm2 and volume 0.66 sm3. Lithium contained alloys was processed for obtaining form of anode place in current sources or powdered with next pressing in the mold. Cathode materials (metal oxides: MnO2, Ag2O, V2O5, MoO3, PbO2, CuO; sulfides: TiS2, FeS2, FeS and conducting polymer polyacetylene (PAC)) were powdered also. Inorganic salt LiClO4 1 M dissolved in the organic liquid solvent y-butyrolactone (BL) was used as electrolyte.

For anode materials in the real button types current sources was used lithium alloys with composition from homogeneity range of continuous solid solution LiZnxAl1-x (x = 0-1) and ternary compound Li2.5-1.5Zn0.5-1.5Sn. Both this phases crystallized in Zintl phase structure type NaTl (space group Fd3m) [7]. Homogeneity ranges of solid solutions LiZnxAl1-x (x = 0-1) and ternary compound Li2.5-1.5Zn0.5-1.5Sn are presented in the Table 1.

Table 1

Lattice parameters and composition of the alloys homogeneity ranges of solid solutions LiZnxAl1-x and ternary compound Li25-15Zn05-15Sn

LiZnxAl1-x

 

 

Li2.5-1.5Zn0.5-1.5Sn

 

 

Composition

1 a, A

1 Reference

Composition

1 a, A

1 Reference

LiZn

6.221

[8]

Li2.5Zn0.5Sn

6.307(3)

[11]

LiZn0.9Al0.1

6.2240(1)

[9]

Li2ZnSn

6.376(3)

[11]

LiZn0.8Al0.2

6.2470(1)

[9]

Li1.5Zn1.5Sn

6.449(5)

[11]

LiZn0.7Al0.3

6.2592(1)

[9]

 

 

 

LiZn0.6Al0.4

6.2697(1)

[9]

 

 

 

LiZn0.5Al0.5

6.2819(1)

[9]

 

 

 

LiZn0.4Al0.6

6.2987(1)

[9]

 

 

 

LiZn0.3Al0.7

6.3102(1)

[9]

 

 

 

LiZn0.2Al0.8

6.3347(1)

[9]

 

 

 

LiAl

6.360

[10]

 

 

 

Results of testing of alloy Li2ZnAl by crystal structure refinement was presented as an example on Fig. 1.

Li50Zn25AI25

sn2 5.prf:

Yobs

- Ycalc

- Yobs-Ycalc

I       Bragg position"

7700 6800 ^ 5900 7" 5000 J 4100 ы 3200 2300 1400 500 -400 -1300

7        12       17       22       27       32       37       42       47       52 57

2в(°)

Fig. 1. Observed and calculated X-ray powder diffraction patterns of Li2ZnAl together with their difference curve

Electrochemical characteristics of batteries with LiZnxAl1-x anode and different cathodes with organic electrolyte liquids (LiClO4 1 M dissolved in the y-butyrolactone (BL)) are presented in the Table 2.

і

11

і і

Table 2

Voltage and energy density for the investigated electrochemical systems

System

Voltage (E), [V]

1 Energy density (W) [W h/kg]

LiZnxAl1-x-MnO2

2.80-2.27

180-110

LiZnxAl1-x-TiS2

2.50-1.90

130-100

LiZnxAl1-x-Ag2O

3.04-2.21

160-100

LiZnxAl1-x-FeS2

2.00-1.70

110-90

LiZnxAl1-x-(PAC)

3.12-2.42

240-180

LiZnxAl1-x-V2O5

2.80-2.30

190-140

LiZnxAl1-x-MoO3

2.50-1.80

140-110

Li2.5-1.5Zn0.5-1.5Sn -PbO2

2.82-2.05

105-80

Li2.5-1.5Zn0.5-1.5Sn-FeS

1.75-1.50

90-60

Li2.5-1.5Zn0.5-1.5Sn-CuO

2.10-1.80

110-90

Discharge curves for some investigated electrochemical systems presented on the

Figs. 2-5.

Li-Zn-{Al, Sn} ZINTL PHASE ALLOYS ...

0 -|-1-1-1-1-1-1-1-1

0 50        100      150       200      250      300       350 400

t, min

Fig. 4. Discharge curve for the LiZnxAl1-x-PAC system

0        25       50       75       100      125      150      175      200 225

t, min

Fig. 5. Discharge curve for the LiZnxAl1.x-Ni2O3 system

1.6 1.4

1.2 --^

0.8 0.6 0.4 0.2

0

-1-1-1-1-1-1-1-

0 50       100      150       200      250      300      350 400

t, min

Fig. 6. Discharge curve for the LiZnxSn1.x-HgO system

I J 1.2 1

Q.S 0.8 Q.i

0.2 0

1C0

150

200

t, min

250

300

Fig. 7. Discharge curve for the LiZnISn1__I-Ag2O system

Li-Zn-{Al, Sn} ZINTL PHASE ALLOYS ...

Nominal voltage of current sources on the base of the LiZnxAl1-x (x = 0-1) phases increasing with increasing of Al content independently of cathode materials. Therefore energy density is close to the classic LiAl anode and in some case is higher. It's can be explained by higher stability of the Zn-contained ternary phases in organic liquid electrolyte and lower ability to dendrite formation. Current sources with Li2^-L5Zn05-L5Sn anode material characterized by lower energy density but stability of these anode materials also is good.

Acknowelegment

WTZ project N UKR02017 and grants of Ministry of Science and Education of Ukraine N 013U001892 and N 0106U001309 partially supported this work.

1. Broussley M., Biensan P., Simon B. Lithium insertion into host materials: the key to success for Li ion batteries // Electrochim. Acta. 1999. Vol. 45. No 1-2. P. 3-22.

2. Сергеев А.Г., Михайлова СЛ. Влияние катодов, содержащих фталоцианины d-металлов, на разрядныге характеристики элементов системы Li/SOCl2 при высокой плотности тока // Abstracts of Conference "Lithium current sources". Novocherkask, 11-14 September 1990. P. 165.

3. Whittingham M.S. Chemistry of intercalation compounds: Metal guests in chalcogenide hosts // Prog. Solid State Chem. 1978. Vol. 12. No 1. P. 41-99.

4. Vincent C.A., Scrosati B. Modern Batteries // Arnold publisher, co published by John Wiley & Sons Inc. London, 1997.

5. Schwarzenbach D. Program LATCON // UNI Lausanne. 1975.

6. Roisnel T., Rodriguez-Carvajal. FullProf. 98 and WinPLOTR: New Windows 95/NT

Applications for Diffraction. Commission of Powder Diffraction // J. Mater. Sci. Forum. 2001. Vol. 378-381(1). P. 118.

7. Zintl E., Dullenkopf W. Uber den Gitterbau von NaTl und seine Beziehung zu den Structuren vom Typus des P-Messings // Z. Phys. Chem. 1932. B. 16. S. 195-205.

8. Zintl E., Brauer W.G. Uber die Valenzelektronenregel und die Atomradien unedler Metalle in Legierungen // Z. Phys. Chem. 1933. B. 20. S. 245-271.

9. Dmytriv G., Pauly H., Ehrenberg H. Solid solutions with NaTl structure in the Li-Ag-In and Li-Zn-Al systems // Abstract of Xth International Seminar on Physics and Chemistry of Solids. Lviv, 6-9 June 2004. P. 76.

10. Zintl E., Woltersdorf G. Gitterstruktur von LiAl // Z. Electrochem. 1935. B. 41. N 12.

S. 876-879.

11. Pavlyuk V.V., Opainych I.M., Dmytriv G.S., Bodak O.I. Investigation of the Ce-Ni-Mg and Li-Zn-Sn systems // Abstract of XIth International Conference on Solid Compounds of Transition Elements. Wroclaw, 5-8 July 1994. P. 105.

СПЛАВИ ФАЗ ЦИНТЛЯ СИСТЕМ Li-Zn-{Al, Sn} ДЛЯ АНОДНИХ МАТЕРІАЛІВ ЛІТІЄВИХ БАТАРЕЙ

Г. Дмитрів х, В. Павлюк х, I. Тарасюк х, Г. Паулі2, Г. Еренберг 2, Б. Марціняк 3, В. Прохвіч 3, Г. Шредер 4

1 Львівський національний університет імені Івана Франка, вул. Кирила і Мефодія, 6, 79005 Львів, Україна

2 Інститут матеріалознавства, Технічний університет м. Дармштадт, Петерсенштрассе, 23, D-64287 Дармштадт, Німеччина

3 Інститут хімії і захисту довкілля, Університет /на Длугоша, вул. Армії Крайової, 13/15, 42200 Ченстохова, Польща

4 Універ итет імені Адама Міцкевича, вул. Грюнвальдська, 6, 60780 Познань, Польща

Сплави з області гомогенності твердого розчину LiZnxAl1-x (x = 0-1) та тернарної сполуки Li25-15Zn05-15Sn досліджували як анодні матеріали літієвих батарей. Усі тестовані фази кристалізуються зі структурою фаз Цинтля, структурний тип NaTl (просторова група Fd3m). Хімічні джерела струму з вказаними анодними матеріалами характеризуються напругою 1,5-3,12 В та питомою енергією 60-240 Вт год/кг залежно від матеріалу катоду та складуматеріалуаноду.

Ключові слова: фази Цинтля, анодні матеріали, літієві батареї.

Стаття надійшла до редколегії 02.10.2006 Прийнята до друку 21.11.2006

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G Dmytriv, V Pavlyuk, I Tarasiuk - Li-zn-{al sn} zintl phase alloys for the anode materials of lithium batteries