22nd International Seminar on Primary and Secondary Batteries Fort Lauderdale, Florida

Peter Guggenheim of Valence Technology Inc. discussed the performance and safety characteristics of phosphate-based Li-ion batteries as compared to metal-oxide batteries. The inherent properties of the cathode material itself define the ultimate safety of a power system. Phosphate-based cathodes possess a structural advantage that limits the likelihood of oxygen liberation and combustion, thereby translating into safer Li-ion batteries.

Their forecast of the Li-ion market is given in the table below:

Lithium-Ion Market ($billion)

Mobility Consumer Military Other Vehicular Industrial 2004 3.5 0.48 0.4 0.2 0.0 0.0 2010 8.0 5.0 2.0 0.0 2.0 6.5

Valence makes both lithium iron phosphate and lithium vanadium phosphate batteries for various applications at their plant in China. They forecast a 10-year life at room temperature for the system. The Li-ion, with phosphate cathode materials, does not go into thermal runaway until above 250C. Theirs is viewed as being the safest Li-ion battery.

Norman Allen reviewed the UltraCell fuel cell technology development for notebooks and other applications. The technology is a spinoff from the Lawrence Livermore National Laboratory. The fuel is methanol but the system reforms methanol into hydrogen for use in the fuel cell. As a result, the cell can operate at higher current densities. UltraCell has developed a 45-watt unit for notebook computers. The unit is under test at several potential users. It will yield a 400Wh mission on a 200cc cartridge.

M. Holzapfel of Paul Scherrer Institute presented their work on silicon (Si) anodes for Li-ion cells. Si was vapor deposited onto a graphite substrate from silane in an argon carrier gas. The nano Si particles (size ca. 20nm) were homogeneously distributed over the surface of the graphite particle. To make an electrode, the nanocrystal particle of Si on graphite was mixed with TIMREX KS6 and carbon black, with 10% PVdF as the binder. The mix was cast onto a treated copper foil substrate as the current collector. The electrodes were highly reversible with a capacity of about 900-1000mAh/g. The electrodes had good cycle life and could deliver over 80% of their capacity at 8C discharge rate.

Kamel Urbal of Intel reviewed their efforts in funding new ventures to increase the run-time of batteries that power notebook computers. Notebooks are finally enabling the “personal” of what is called personal computing, any time, anywhere. In 2001, 24 million notebooks were sold and last year the number rose to 47 million, of which 65% had wireless capability. That is expected to rise to 90% in 2005. Battery life is the often-heard complaint. Intel Capital has focused its investment activities into three thrusts to increase runtime: 1) increased battery capacity, 2) development of new higher energy chemistries, cell constructions and fuel cells, and 3) fast charging technologies, alternate charging algorithms, etc. Their goal is to balance a business relationship with a strategic financial investment. In 2004, Intel Capital participated in 1100 deals and invested $130 million of which 40% were outside the U.S.

Christophe Pillot of Avicenne presented their market forecasts and applications for small sealed cells. The following values were estimated from his charts.

Cellular Phones

New Replacement Li-ion Li-ion Polymer NiMH 195* 430* 80% 13% 7% 100* 430* 70% 30% 0%

Notebook Computers

New Li-ion NiMH 47* 90* 10% 69* 10* 0%

Camcorders

New Replacement Li-ion NiMH NiCd 4.4* 2.0* 45% 5% 53% 13.6* 17.6* 70% 5% 20%

The 2004 market was 2.5 billion cells

Li-ion Li-ion Polymer   $3700* 500*   *million

Cell Usage

Notebook Cellular Telephone Camcorders Other 30% 58% 6% 6%

Christina Lampe-Onnerud reviewed the cost structure of Li-ion batteries. The cost of cobalt and nickel has varied widely over the past 10 years. Cobalt low and high were at $15.21/kg in 2002 and at $64.40 in 1995. It currently is $39.69/kg. This has led to a significant activity to develop lower cost cathode materials. Nickel has had a similar variation with a low of $4.63/kg and a high of $14.10/kg. It currently is at the high of $14.10/kg. This compares to a cost of $10/kg for the manganese compounds.The 1/3 mixed oxides currently come in at about $30/kg. The capacity of these compounds is similar to the cobalt material but the 1/3 compound discharges at a lower voltage. Cost is the only advantage of this material. The higher performance stabilized nickel-cobalt materials offer a way for higher capacity and lower cost with good safety characteristics.

Thomas Dougherty of Johnson Controls (JCI) described their work on developing NiMH and Li-ion batteries for automotive applications. JCI currently has the capability to produce over 86 million car batteries and has sales of about $2.3 billion. The hybrid system is more than a battery. It includes the electric motor, battery controller including cell balancing, wiring harness and hardware. Battery costs grow in proportion to the voltage as do warranty costs. JCI prefers a prismatic cell design with through-the-partition inter-cell connections to reduce cost and lower internal resistance. Long life requires a balance of energy, power and the proper state of charge operating window. Li-Ion has an advantage of significantly fewer cells and higher specific power than lead acid or NiMH for the same battery voltage. NiMH is the technology of today but Li-ion can replace it when cost and abuse tolerance are on a par with NiMH.

N. Yamamoto of Panasonic reported on their efforts to develop a nickel-manganese cathode material. They have developed a solid solution mixture of LiNiO2 and LiMn2O4. The new material has slightly higher capacity and superior rate capability than the cobalt materials with the thermal stability and safety of manganese.

U. Wietelmann of Chemetall gave an overview of the available information on the new lithium bisoxalato borate (LiBOB) electrolyte salt. Full registration as the chemical should be complete by May 2005 in Europe. The registration process is in progress in Japan and the U.S. It is neither corrosive nor mutagenic with an LD50 of 300 mg/kg. It will be classified as “Harmful.” The formation process in LiBOB electrolytes differs from the formation in LiPF6 electrolytes. It will be necessary to have a careful balancing of the anode/cathode capacity balance. There is good performance with manganese spinel and phosphate cathode materials but is unstable at higher temperatures with cobalt materials. Tests show reduced manganese dissolution in contact with a LiBOB electrolyte than with a LiPF6 electrolyte.

M. Thackeray of Argonne National Laboratory described their work on manganese-based materials for Li-ion cells. They have been working with layered manganese compounds with other metals incorporated into the lattice, including cobalt and nickel. “Layered-layered”structure of xLiMn-O3 • (1-x) LiMO2 and “layered-spinel” xLi2MnO3 • (10x)LMn2O4 electrodes with (M=Mn, Ni, Co) have incoherent composite structures. The inactive Li2MnO3 acts as a structural dopant to stabilize layered LMO2 and to reduce oxygen activity at the surface of charged electrode particles. Li2O removal during the initial charge increases MnO2 content and capacity of composite material. A rechargeable capacity of 250mAh/g or more can be achieved when charged to 5 volts.This is similar to the results of I. Davidson reported at IMLB-12 with chromium substitutions. The capacity of these materials is significantly higher than that of presently used cobalt cathode materials. These manganese materials have excellent safety characteristics and use electrolytic manganese dioxide (EMD) as the starting material. EMD sells for about $1/lb so the manganese materials will be significantly less expensive than the cobalt materials. EMD is a commodity on the world market and should not be subject to large swings in price. These materials could well be in the next round of service improvements.

Y. Gao of FMC introduced a new stabilized lithium metal powder (SLMP) for use in fabrication of lithium and Li-ion batteries. It can be handled in a regular dry room and coated on foils to form electrode structures. It has a particle size in the range of 10 to 50 microns. It can lithiate graphite when contacted with electrolyte and can be used to balance the first charge loss on formation of Li-ion cells. It can enable the use of low-cost cathode materials, such as EMD or other non-lithiated cathode materials. As an example, when used with heat-treated EMD as the cathode, it forms a spinel on charging with a capacity of 200mAh/g during first charge.