Well-defined lead-acid battery active materials
OwnerNigel BECKNELL, Pietro Papa Lopesinventors
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Abstract
Described herein is crystalline PbSO4 comprising tabular and/or diamond-shaped crystals having an average crystal size, as determined by dynamic light scattering and particle imaging using a transmission electron microscope, in the range of about 10 nm to about 2 μm, wherein at least about 80% of the PbSO4 crystals have diameters within about ±20% of the average diameter. Also described herein electrodes, lead-acid electrochemical cells, and lead-acid batteries comprising the crystalline PbSO4.
Claims23
An electrode for a lead-acid battery comprising, in an initial, discharged state, a paste of tabular and/or diamond-shaped PbSO4 crystals in a conductive grid framework;
- wherein the crystals have a selected average crystal size, as determined by dynamic light scattering and particle imaging using a transmission electron microscope, in the range of about 10 nm to about 2 μm, and at least about 80% of the PbSO4 crystals in the paste have diameters within about ±20% of the average diameter.
A method of preparing PbSO4 crystals with a tabular and/or diamond crystal shape and a selected average crystal size;
- the method comprising:
- mixing equimolar amounts of a Pb(2+)-containing aqueous solution and a SO4(2−)-containing aqueous solution into an acidic crystal-growth control solution comprising a crystal grrowth modifier and acetic acid at a pH in the range of about 1 to 5, at a defined rate of addition in the range of 0.01 micromoles to 1000 millimoles of Pb(2+) and SO4(2−) per minute, thereby forming tabular and/or diamond-shaped PbSO4 crystals that have an average crystal size, as determined by dynamic light scattering and particle imaging using a transmission electron microscope, of about 10 nm to about 2 μm, with a particle size distribution in which at least about 90% of the crystals have a particle size within about 20% of the average diameter;
- washing the crystals with water to remove and the crystal-growth modifier and soluble salt contaminants;
- and
- recovering the crystals.
Crystalline PbSO4 comprising tabular and/or diamond-shaped crystals having an average crystal size, as determined by dynamic light scattering and particle imaging using a transmission electron microscope, of about 50 nm to about 2 μm, with a particle size distribution in which at least about 90% of the crystals have a particle size within about 20% of the average diameter.
Dependencies are inferred from the claim text.