MacRae Maxfield

Secondary batteries with electroactive polymer electrodes

Abstract The application of electroactive conductive polymers to nonaqueous secondary batteries is reviewed. Data are presented on the performance of oxidized polyacetylene, poly(3-butylthiophene-co-3-methylthiophene), poly(dimethoxyphenylene vinylene), polypyrrole, and polyaniline as positive electrode materials, and on reduced polyacetylene, polyphenylene and poly(dimethoxyphenylene vinylene) as negative electrode materials.

High energy density batteries derived from conductive polymers

Abstract Allied-Signal has developed batteries which derive their superior performance from the unique combination of properties offered by conductive polymers: electroactivity, mechanical resiliency, and combined ionic and electronic conductivity. Composite electrodes fabricated from conductive polymers and alkali-metal alloys operate with high efficiency and high cycle life. Composite negative electrodes have been combined with cation inserting positive electrodes such as LixV6O13 and NaxCoO2 to produce high energy density cells having excellent cycle life and a high average voltage, 1.9 V and 2.5 V, respectively. Early Prototype AF-size cells in welded steel cans have demonstrated up to 65 mWh/g (160 mWh/cm3) and 70 mWh/g (170 mWh/cm3) for sodium and lithium cells, respectively. Energy densities as high as 100 mWh/g (260 mWh/cm3) are projected for efficiently packaged sodium cells charged to a higher average voltage (2.8V).

The Optical, Electrochemical and Structure/Property Relationships of Poly(Heteroaromatic Vinylenes

Abstract Convenient conducting polymer processibility has been achieved recently by the development of soluble precursor polymers for polyacetylene (PA)1, polyphenylene (PPP)2, and poly(ppheny1ene vinylene) (PPV)3. In each case, a two-stage route was use+ First, a high molecular weight, soluble, non-conjugated precursor polymer was prepared that could be easily solution cast into films. Then, thermal treatment converted the precursor polymer to the final conjugated polymer. Unfortunately, neither doped PA, doped PPP, nor doped PPV has long term stability in ambient air, which severely limits their usefulness in wide scale electronic applications.

Alloy/conducting-polymer composite electrodes: electrolytes, cathodes, and morphology

Abstract Composites comprising alkali metal alloys and alkali metal doped conductive polymers constitute a class of electrode materials useful in rechargeable cells. Composite electrodes made with poly( p -phenylene) (PPP) and polyacetylene (PA) exhibit high rechargeability for donor doping (cation insertion) in ether electrolytes such as NaPF 6 in 1,2-dimethoxyethane (DME) and LiPF 6 in 2-methyltetrahydrofuran (MTHF), plus rechargeability, at restricted potentials, in solvents such as sulfolane and benzonitrile. NaPb, LiPb, and LiAl alloys, formed as composites with PPP and PA, have been cycled exhaustively with excellent charge capacity retention. These composites form rechargeable cells with a variety of cation-inserting cathodes. In particular, balanced cells having NaPb/PPP anodes and NaCoO 2 cathodes have been cycled 250 times with little capacity loss. The good performance of these composites is due, in part, to the basic fibrillar morphology of the polymer, which becomes evident during cycling. After several cycles, the composites possess the fibrillar structure of pure polymer electrodes, with crystalline alloy uniformly distributed on or in the fibrils in particles of less than 0.2 μm. This structure, particularly when the fibrils are swollen with electrolyte, facilitates rapid transport of ions and electronic charge throughout the electrode.