BATTERY RESEARCH AT ARGONNE NATIONAL LABORATORY

Michael M. Thackeray

Electrochemical Technology Program Chemical Technology Program

Argonne, IL 60439 A~g~iXK? N a h n d ~ ~ b Q l ' 2 h r y

The submitted manuscript has been created by the University of Chicago as Operator of Argonne National Laboratory ("Argonne") under Contract No. W-31-109- ENG-38 with the U.S. Department of Energy. The US. Government retains for itself, and others acting on its behalf, a paid-up, nonexclusive, irrevocable worldwide license in said article lo reproduce, prepare derivative works, distribute copies to the public, and perform publicly and display publicly, by or on behalf of the Government.

October, 1997

To be presented at the Exploratory Technology Research session at the DOE-sponsored Automotive Technology Development Customers' Coordination Meeting (CCM), October 27-30, 1997, Dearborn, Michigan

DISCLAIMER

This report was prepared as an account of work sponsored by an agency of the United States Government. Neither the United States Government nor any agency thereof, nor any of their employees, makes any warranty, express or implied, or assumes any legal liability or responsibility for the accuracy, completeness, or use- fulness of any information, apparatus, product, or process disclosed, or represents that its use would not infringe privately owned rights. Reference herein to any spe- cific commercial product, process, or service by trade name, trademark, manufac- turer, or otherwise does not necessarily constitute or imply its endorsement, recom- mendation, or favoring by the United States Government or any agency thereof. The views and opinions of authors expressed herein do not necessarily state or reflect those of the United States Government or any agency thereof.

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BATTERY RESEARCH AT ARGONNE NATIONAL LABORATORY

Michael M. Thackeray

Electrochemical Technology Program Chemical Technology Program Argonne National Laboratory

Argonne, IL 60439

Argonne National Laboratory (ANL) has, for many years, been engaged in battery-related R&D programs for DOE and the transportation industry. In particular, from 1973 to 1995, ANL played a pioneering role in the technological development of the high-temperature (400°C) lithium-iron disulfide battery. With the emphasis of battery research moving away from high temperature systems toward ambient temperature lithium-based systems for the longer term, ANL has redirected its efforts toward the development of a lithium- polymer battery (60 - 80°C operation) and room temperature systems based on lithium- ion technologies. ANL’s lithium-polymer battery program is supported by the United States Advanced Battery Consortium (USABC), 3M and Hydro-Quebec, and the lithium-ion battery R&D efforts by U.S. industry and by DOE.

In 1994, ANL expanded its materials research activities to support the lithium- polymer and lithium-ion battery initiatives. The major objectives of the exploratory research projects are 1) to develop new or modified electrode materials with enhanced properties relating to performance, safety and cost, 2) to evaluate the electrode materials in laboratory test cells, 3) to undertake modeling studies of electrode structures and electrochemical processes on an atomic scale to guide synthesize efforts

and to predict new materials that have not yet been synthesized in the laboratory.

Lithium-ion batteries operate by an electrochemical mechanism whereby lithium ions are shuttled between two host electrode structures during discharge and charge with concomitant oxidation and reduction processes occurring at the host electrodes. A major advantage of lithium-ion battery technology is that a wide variety of insertion electrode materials exist. Therefore, different chemistries can be used to tailor the voltage of the lithium battery. Examples of host electrodes include metal oxides, metal sulfides, intermetallic compounds (alloys) and various carbon materials. Several lithium-ion systems have already been commercialized, the best known being the LiXC6/Li~-,CoO:! system which delivers an average 3.5 V. Other lithium-ion battery products are:

LixC6/LiMn204 3.5 v LiXSnO,/Li1-,CoO;! 3.5 V LiAl/Li,V205 3 v LiAl/Li,MnOz 2.8 V LiqTi50 I 2/Li,Mn02 1.5 V

High-voltage lithium-ion cells have inherent safety limitations. For example, finely divided and highly reactive lithium can be deposited at the negative electrode in liquid organic electrolytes during high rates

of charge, or if cells are overcharged. The positive electrode materials in these cells are strong oxidizing agents, particularly at the top of charge. There is, therefore a need to modify existing electrode materials or develop new ones to improve the performance and safety aspects of current lithium-ion battery technology.

Manganese oxide electrodes are attractive candidates for lithium batteries, because they offer a relatively high voltage vs. lithium (3 V to 4 V) and a relatively high theoretical capacity (308 mANg). Manganese oxides are also environmentally acceptable and inexpensive materials. Furthermore, the family of manganese oxides offer a large number of structure types from which to chose. The spinel system Li,Mn204 (O<x<l) is attractive as an electrode for 4 V lithium-ion cells, but has a limited capacity (theoretical capacity = 148 mANg). On the other hand, MnO2 electrodes that offer 3 V vs lithium have a significantly higher theoretical capacity (308 mAhIg); they are of particular interest for lithium-polymer batteries.

ANL has focused much of its research effort on the development of a- Mn02 electrodes for 3 V lithium battery applications. cc-MnOz has a hollandite-type structure which is normally stabilized by large cations, such as Ba2+ or K+ that reside in the large (2x2) tunnels of the structure. The stabilizing cations impede the diffusion of lithium ions during charge and discharge, which limits the use of these electrodes in lithium cells. A significant improvement in the performance of a-MnOz electrodes has been made by using lithium oxide molecules (LiZO) to stabilize the a-MnO2 framework. Lithia-stabilized electrodes of nominal composition 0.15Li20.Mn07 can provide a rechargeable capacity of 200 mAh/g in

contrast to unstabilized a-Mn02 electrodes which show a typical rechargeable capacity of 120.-140 mANg. The oxygen ions from the Liz0 molecules reside in the crystal structure at approximately the same positions as the stabilizing Ba2+ or K' ions in hollandite (BaMnsOl6) and cryptomelane (KMnsO 16), respectively.

Vanadium oxides are attractive from the view point that they can offer higher electrode capacities compared to manganese oxides, but at a slightly lower voltage. Ab initio structure calculations of the Lil+xV30g system (O<x<4) using the plane-wave pseudo potential method have been made which are providing valuable information about the phase stability of the system. Of particular significance was the ability of the modeling approach to determine the positions of all four lithium ions in the lithiated Li4V308 structure; only three lithium ion positions could be determined unequivocally by single crystal X-ray diffraction methods.

The exploratory research efforts at ANL will continue to focus predominantly on first-row transition metal oxide electrode materials. Specific attention will be paid to electrochemical couples that could be used to develop a high-power, energy storage device for hybrid electric vehicle applications.

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Battery Research at Argonne National Laboratory

Argonne Nat e, IL 60439

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Different chemistries can be used to tailor the voltages of lithium batteries High voltage lithium-ion batteries have safety limitations at the top of charge An opportunity exists to improve the performance and safety of lithium batteries ANL focus is on first row transition metal oxides, notably manganese oxides

Electrochemical Technology Program Argonne National Laboratory

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MnO, has cost, safety and environmental advantages over other transition metal oxides

"Pure" MnO, materials are unstable to lithiation - Li X MnO, structures undergo a Jahn-Teller distortion at x ==: 0.5 causing structural fatigue during electrochemical cycling

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Elect roc h emica I Tech no logy P rog ra m Argonne National Laboratory

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The electrochemical behavior is strongly dependent on the precursor materials from which the a-MnO, electrodes are made

Mn,O, is significantly less expensive than Li,MnO,

Elect roc h em ica I Techno logy P rog ra m 1

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Microstructural Studies of a-MnO,

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Electrochemical Technology Program Argonne National Laboratory

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Elect roc h emica I Technology P rog ra m Argonne National Laboratory

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Elect roc hemica I Technology P rog ra m Argonne National Laboratory

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Electrochemical Technology Program Argonne National Laboratory

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Elect ro c h emica I Techno logy P rog ra m Argonne National Laboratory

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Future Directions

The exploratory research efforts at ANL will continue to focus predominantly on first row transition metal oxide electrode materials

Specific attention will be paid to electrochemical couples that could be used to develop a high power, energy storage device for hybrid electric vehicles

Elect roc h emica I Techno logy P rog ra m Argonne National Laboratory

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Acknowledgments

Significant contributions to this work were made by Dr. C. S. Johnson (ANL), Dr. R. Benedek (ANL), Dr. S. A. Hackney (MTU), and Ms. Y. Shao-Horn

(MTU)

Support from the United States Advanced Battery Consortium/3M/Hydro-Quebec, and the Department of Energy under Contract No. 31-109-Eng-38, is gratefully acknowledged

Elect roc h emica I Tech nology Program Argonne National Laboratory

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Publ. Date (11) 1 ? 7

uc Category (19) Sponsor Code (1 8) D D E / / m , - y f

uc 9 D Q ', ~ O ~ / E K

19980619 142

DOE