Ultrathin polymer electrolyte having high conductivity

DETAILED DESCRIPTION OF THE INVENTION Cathode and anode half elements useful in constructing the electrochemical cells of the present invention are known in the art.
The most typical anode is the lithium anode prepared by providing a layer of lithium metal on a metal foil (such as nickel or copper) which functions as the current collector.
The cathode half element is a composite of an insertion compound, an electronically conductive filler, and the polymer electrolyte described above.
Insertion compounds known in the art are useful in cathode compositions of the invention.
Typical examples of insertion compounds include transition metal oxides, sulfides, and selenides, such as V.
sub.
6 O.
sub.
13, TiS.
sub.
2, MnO.
sub.
2, MoS.
sub.
3, Cr.
sub.
3 O.
sub.
6, Li.
sub.
x V.
sub.
3 O.
sub.
8, and V.
sub.
2 O.
sub.
5.
The preferred materials are vanadium oxides such as V.
sub.
2 O.
sub.
5 and V.
sub.
6 O.
sub.
13.
The preferred vanadium oxide compound, V.
sub.
6 O.
sub.
13, is prepared by the thermal decomposition of ammonium metavanadate.
For electronic conductivity, the cathode composition contains an electronically conductive filler, the most typical example of which is carbon black.
For ionic conductivity one of the polymer electrolytes described herein is incorporated into the cathode composite.
This composition is compounded in a know manner and coated on a layer of the polymer electrolyte described below or on a second metal foil member which functions as a current collector to provide the cathode.
The polymers used in the electrolyte composition of the present invention may be thermoplastic or thermoset.
General examples of useful polymers are described in U.
S.
Pat.
No.
4,303,748 to Armand and European Application 0 145 498 to Cook.
These polymers have repeating units containing at least one heteroatom such as an oxygen or nitrogen atom.
They can be represented as polymers having the repeating unit ##STR1## wherein R is hydrogen or a group Ra, --CH.
sub.
2 ORa, --CH.
sub.
2 OReRa, --CH.
sub.
2 N(CH.
sub.
3).
sub.
2, in which Ra is an alkyl group containing 1 to 16 carbon atoms and preferably 1 to 4 carbon atoms or a cycloalkyl group containing 5 to 8 carbon atoms, and Re is an ether group of formula --CH