A polymer electrolyte membrane for a fuel cell includes a cross-linking polymer in which a polyhedral oligomeric silsequioxane (POSS) is cross-linked with a hydrocarbon-based polymer and a membrane-electrode assembly for a fuel cell includes the polymer electrolyte membrane.

Provided are a polymer electrolyte composition, an electrolyte membrane, a membrane electrolyte assembly, and a fuel cell. The polymer electrolyte composition according to an exemplary embodiment of this application includes a first solvent, a second solvent which is different from the first solvent, and a polymer which is reacted with the first solvent and the second solvent, in which the polymer includes a functional group which reacts with the first solvent by a first reaction energy and with the second solvent by a second reaction energy, and the second reaction energy is smaller than the first reaction energy.

Provided are a polymer electrolyte composition, an electrolyte membrane, a membrane electrolyte assembly, and a fuel cell. The polymer electrolyte composition according to an exemplary embodiment of this application includes a first solvent, a second solvent which is different from the first solvent, and a polymer which is reacted with the first solvent and the second solvent, in which the polymer includes a functional group which reacts with the first solvent by a first reaction energy and with the second solvent by a second reaction energy, and the second reaction energy is smaller than the first reaction energy.

The invention relates to copolymers comprising a chain of siloxane repeat units of at least two different types, a first type of siloxane repeat unit comprising at least one OH group on the silicon atom of the siloxane repeat unit and a second type of repeat unit comprising at least one pendant chain on the silicon atom of said repeat unit, this pendant chain consisting of a polymer chain comprising a chain of repeat units carrying at least one group of formula PO.sub.3R.sup.1R.sup.2 wherein R.sup.1 and R.sup.2 independently represent a hydrogen atom, an alkyl group or a cation.

Composites of porous nano-featured silicon and various materials, such as carbon, are provided. The composites find utility in various applications, such as electrical energy storage electrodes and devices comprising the same.

Composites of porous nano-featured silicon and various materials, such as carbon, are provided. The composites find utility in various applications, such as electrical energy storage electrodes and devices comprising the same.

Porous silicon and methods for preparation and use of the same are disclosed. The porous silicon materials have utility either alone or in combination with other materials, for example, combined with carbon particles for energy storage applications.

Porous silicon and methods for preparation and use of the same are disclosed. The porous silicon materials have utility either alone or in combination with other materials, for example, combined with carbon particles for energy storage applications.