Sri International

Polyfuel, Inc.

Philip Cox

Subhash C Narang

Susanna C Ventura

Ngan Tran

Suk-Yal Cha

Gouyan Hou

Anh Duong

A method of preparing catalyst agglomerates for electrochemical devices is provided. The method comprises dispersing particles of a catalyst in a non-aqueous solvent to form a dispersion of the catalyst, adding an ion conducting polymer in a dilute solution to the dispersion of the catalyst under agitation to form catalyst agglomerates, and stirring the dispersion of the catalyst and the catalyst agglomerates to control the growth of the agglomerates. A directly applicable catalyst composition is also provided. The catalyst composition comprises the catalyst agglomerates prepared according to the present invention, a solvent to plasticize surfaces of the catalyst agglomerates and the membrane, and a non-aqueous carrier solvent.

Catalyst agglomerates for membrane electrode assemblies

Electrodes for secondary (rechargeable) batteries are fabricated using active material particles such as flakes, fingers, projections, needles, threads, fibers, pods, hairs, ribbons and the like, which have an aspect ratio of at least 1:3:1. The high aspect ratio, in combination with relatively shallow discharge cycles, provides high power of at least 800 W/kg sustainable over at least ten seconds, high energy of at least 7 W-hr/kg, and a high cycle life of at least 250 cycles. Selection of parameters also provides power to energy ratios for high power, high energy batteries of at least 10. Preferred chemistries for the novel batteries include lithium ion, and preferred active materials include carbon, metal oxides and metal. Batteries including the novel technology can advantageously be used in electric vehicles, consumer electronics, electrical appliances, and industrial applications such as battery backup systems and switches.

Ion battery using high aspect ratio electrodes

Electrodes are manufactured using a fire-retardant solvent and a polymerizable monomer. Electrodes according to the present invention are contemplated to find applicability in substantially any electrode containing device, including batteries. A preferred class of fire-retardant solvents includes solvents that generate a fire-retardant gas upon decomposition. One subclass includes compositions that produce carbon dioxide upon decomposition. Other subclasses include species that generate non-CO,gases upon decomposition, such as CO, SO,, SO,, NO, N,O, NO,, or N,. A second preferred class of fire-retardant solvents include solvents that are fire-retardant without generating a fire-retardant gas upon decomposition, and are electrochemically inactive. Subclasses here include the many phosphates, phosphazenes, borates, siloxanes, fluorinated carbonates and fluorinated ethers that are already known to be included in a fire-retardant electrolyte. It is contemplated that the same solvent may be used in both an electrode paste and an electrolyte. It is also contemplated that the same polymer may be used in both an electrode paste and an electrolyte. An exemplary polymer for this purpose is polyvinylidene fluoride (PVDF). In one or both such cases, an electrolyte may advantageously be applied directly to the porous electrode surface, providing excellent interlayer adhesion and thus low interfacial resistance.

Fabrication of electrodes and devices containing electrodes

Secondary metal ion batteries are fabricated using a working electrolyte that is substantially incompatible with the anode material. This is accomplished by forming an SEI on the anode material at least in part using a compatible (i.e., SEI developing) electrolyte, and including a substantially incompatible (non-SEI forming) composition as the working electrolyte.

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San Jose, CA, United States of America

Philip Cox