Phoenix Innovation Polyphosphonate Electrolyte
- From: http://www.acq.osd.mil/mda/mdalink/pdf/50_sum04.pdf
SAFETY FIRST: IMPROVED POLYMER ELECTROLYTE RETARDS FLAME
Polymer magic. A polymer chain containing phosphorus makes a highly
conductive, flame retarding electrolyte for use in batteries. "This would
not have happened had it not been for MDA funding."
-Dr. Brian G. Dixon
Powerful and lightweight, rechargeable lithium-polymer batteries still have
a problem to overcome: they are flammable. A new class of polymer recently
invented may not only improve voltage but also enhance safety.
Phoenix Innovation, Inc. (Wareham, MA), directly as a result of work
performed under MDA SBIR contracts, has patented a polyphosphonate
electrolyte that offers higher conductivity than traditional polyethylene
oxide electrolyte used in lithium-polymer batteries.
As an important bonus, company chemists discovered that the same element
that improved conductivity also retarded flammability. The combination of
higher power density and lower risk is of huge interest to the mobile power
and electric vehicle industry.
"This would not have happened had it not been for MDA funding," said Dr.
Brian G. Dixon, Phoenix president and co-founder. "We wouldn't have anything
to talk about." In 2001, MDA awarded a Phase I SBIR contract to the company
to investigate methods for producing highly conductive polymer electrolyte
and immediately followed up with a Phase II SBIR contract to focus more on
actual production techniques of liquid polymer electrolyte in a pouch
Phoenix is working closely with several other corporations on development
and commercialization of the technology. Originally, Phoenix wanted to focus
on making a solid high-voltage polymer electrolyte. Solid electrolyte offers
the prospect of a lighter weight battery because in principle it would not
need a containment vessel.
However, liquid has an order of magnitude higher ionic conductivity than
solid. In other words, it is much easier and more effective to charge and
recharge through a liquid electrolyte than a solid when dealing with
So in pursuing their discovery, company chemists decided to focus in on the
safety and power density aspects and were less concerned about the liquid
versus solid issue.
The technology does have potential to transition to solid and Phoenix
intends to work towards that objective. Phosphorus is the key to the
equation. Phoenix chemists found that if the "backbone" of a polymer chain
contained phosphorus moieties, the electrolyte retained excellent properties
of high voltage stability and flame retardance.
Traditional polymer electrolytes can be made more stable and flame
retardant, but only by including additives that compromise performance and
add weight. The result is higher power density with low risk. Phoenix
chemists estimate that in the same volume as a traditional 3-volt cell, the
improved polymer electrolyte could push a battery voltage up to somewhere
between 4.5 and 4.8 volts.
According to Dixon, the limiting factor is not the electrolyte but rather
the cathode. Phoenix has developed what it feels is a superior anode
technology, and is currently working with a company with compatible cathode
technology. Making lithium-polymer batteries is not an easy task.
There is a transition process in which the lessons learned in the
laboratory, where batteries are carefully handcrafted one at a time, have to
be translated into high-volume mass production.
Because Phoenix is a small company, it is most actively exploring the
possibility of either licensing its patents or partnering on a formal basis
with a larger firm. However, it is also open to the possibility of growing
into a larger company as the lithium battery market evolves, and towards
that end recently advertised for experienced managers and engineers with
Dr. Brian G. Dixon
Phoenix Innovation, Inc.
20 Patterson Brook Road
PO Box 550
Wareham, MA 02576
Tel: (508) 291-4375
Fax: (508) 291-6307
E-mail: bdixon@ phoenixinnov.com