The isolation materials used in lithium-polymer batteries are reported to have allowed a Compaq portable computer prototype to run for 12 hours on a charge. But since battery manufacture for such products as portable computers and cell phones is largely a custom business, production of lithium-polymer cells has been limited to prototypes thus far and may remain mired in that phase for some time, participants said.

Some industry players, such as marketing and sales director David Williams at Moltech Corp. (Tucson, Ariz.), asserted at Power98 that investments in high-volume manufacturing of the new technology have already been made.

Yet demand remains fragmented even for such relatively well-established technologies as lithium ion, consultant Hideo Takeshita at Japan's Nomura Research Institute said in a plenary address.

Moltech and other promoters of lithium-polymer batteries believe the technology has an edge in terms of "gravimetric density."

Indeed, lithium compounds have been long recognized as offering the most power in the smallest package of any battery chemistry. But lithium electrolyte is unstable: In liquid form it is highly flammable and, in some cases, explosive. Lithium ion renders the technology safe but suppresses some of its potential power.

Battery developers have been working to increase lithium's safety without neutralizing its power-generating properties. Development of lithium polymers has concentrated on containing the lithium electrolyte.

Developers at Elf Atochem North America (King of Prussia, Pa.) believe that Elf's Kynar polyvinylidene fluoride (PVDF) resin will aid in the packaging of lithium-battery gels. The Kynar resin polymer serves as a binder and separator (microporous isolating material for electrolytes) for batteries using lithium-ion polymer technology developed by Bellcore (Morristown, N.J.).

The Kynar resin is promoted as one of the most stable of all commercial resins. It resists strong acids, solvents and reducing agents and is used in a variety of industries, said Michel Foure, Elf Atochem's director of research and development for specialty chemicals and polymers. It not only lets batteries be made in various form factors but also reportedly eases manufacturing, by allowing cells to be reproduced in continuous sheets and then cut to form.

The Bellcore design uses Kynar in the separator and electrodes for lithium-ion batteries. Joseph Carey, market-development manager for Elf Atochem, said he believes the Bellcore formulation will enable thin batteries that fit behind the LCD display of a portable computer.

Vassillis Keramidas, Bellcore's vice president in charge of commercializing formative technologies, called his company's plastic lithium-ion (Plion) battery formulation an extension of lithium-ion technology. He said Plion will offer the safety of lithium ion but at a higher energy density — up to 1,000 mAh from a conventional 18650 (AA cylinder) cell.

Bellcore uses "the same lithium-ion chemistry as 'Japan Inc.,' " Keramidas said. The Bellcore formulation is a hybrid, with a lithium electrolyte in a gel (rather than liquid) form.

But the utility of lithium-polymer formulations has been subject to debate, especially with regard to its costs. Lithium-polymer battery production reflects a common paradox: The technology is unlikely to find a volume market until its costs go down, but it won't be cost-effective until it's in volume production.

"If lithium-polymer was that promising, Japanese battery makers would have gotten into the act," said Robert Serabin, marketing director of battery fuse-maker Thermodisc (Mansfield, Ohio).

Others at Power98 countered with predictions that Japanese manufacturers such as Sony will use lithium-polymer formulations in next-generation portables. But that claim might seem dubious in light of the Nomura Institute's assertion that lithium-ion has yet to reach its full market potential.

Further, thus far, every portable computer and cell phone maker has pursued a different form factor — and has sought to rewrite the energy-density specifications, discharge characteristics and costs around that form factor.

Moltech nonetheless stated that it is conducting a worldwide search for manufacturing partners and that it will enter volume production in 1999.

Bellcore's Keramidas said he believes that Ultralife Batteries Inc. (Newark, N.Y.) is selling laptop-computer batteries with a lithium-polymer formulation and that Mitsubishi is building a 3/4-inch-thick, 3.1-pound computer that uses a lithium-polymer battery.

Other existing lithium-polymer battery makers include Malaysian company Shubila, a supplier to Samsung Electronics.