Disclosed is a carbon-based fiber sheet and a lithium-sulfur battery including the same. The carbon-based fiber sheet for the lithium-sulfur battery is doped with a high concentration of nitrogen and thus plays a role of preventing diffusion by adsorbing lithium polysulfide eluted from a positive electrode during charging and discharging, thereby suppressing a shuttle reaction and thus improving capacity and lifecycle properties of the lithium-sulfur battery.

Disclosed is a carbon-based fiber sheet and a lithium-sulfur battery including the same. The carbon-based fiber sheet for the lithium-sulfur battery is doped with a high concentration of nitrogen and thus plays a role of preventing diffusion by adsorbing lithium polysulfide eluted from a positive electrode during charging and discharging, thereby suppressing a shuttle reaction and thus improving capacity and lifecycle properties of the lithium-sulfur battery.

Pitch compositions suitable for spinning may comprise: a pitch having a softening point (SP) below 400 C. and is capable of achieving a radial Hencky strain prior to break of about 0.7 to about 10, at spinning temperature (T.sub.s) ranging from about SP30 C. to about SP+80 C. Methods for producing a carbon fiber from a pitch composition at a temperature within a spinning temperature (T.sub.s) range may comprise determining a temperature range wherein the maximum radial Hencky strain (.sub.R) lies above a minimum process radial Hencky strain, and wherein the minimum process radial Hencky strain is within a range of about 0.7 to about 10. The spinning temperature (T.sub.s) range may be determined by measuring a maximum radial Hencky strain (.sub.R) prior to break at a series of different temperatures and strain rates. Carbon fiber composites may comprise of the said carbon fiber.

Pitch compositions suitable for spinning may comprise: a pitch having a softening point (SP) below 400 C. and is capable of achieving a radial Hencky strain prior to break of about 0.7 to about 10, at spinning temperature (T.sub.s) ranging from about SP30 C. to about SP+80 C. Methods for producing a carbon fiber from a pitch composition at a temperature within a spinning temperature (T.sub.s) range may comprise determining a temperature range wherein the maximum radial Hencky strain (.sub.R) lies above a minimum process radial Hencky strain, and wherein the minimum process radial Hencky strain is within a range of about 0.7 to about 10. The spinning temperature (T.sub.s) range may be determined by measuring a maximum radial Hencky strain (.sub.R) prior to break at a series of different temperatures and strain rates. Carbon fiber composites may comprise of the said carbon fiber.

A pitch composition suitable for spinning may comprise: a pitch having a softening point temperature (T.sub.sp) of 400 C. or less, and an oxidation onset temperature (OOT) at least 10 C. below the T.sub.sp at a ramp rate of 10 C./min. A carbon fiber may comprise: a carbon fiber produced from a pitch composition, wherein the pitch composition comprises: a pitch having a softening point temperature (T.sub.sp) of 400 C. or less, and an oxidation onset temperature (OOT) at least 10 C. below the T.sub.sp at a ramp rate of 10 C./min.

A pitch composition suitable for spinning may comprise: a pitch having a softening point temperature (T.sub.sp) of 400 C. or less, and an oxidation onset temperature (OOT) at least 10 C. below the T.sub.sp at a ramp rate of 10 C./min. A carbon fiber may comprise: a carbon fiber produced from a pitch composition, wherein the pitch composition comprises: a pitch having a softening point temperature (T.sub.sp) of 400 C. or less, and an oxidation onset temperature (OOT) at least 10 C. below the T.sub.sp at a ramp rate of 10 C./min.

Provided is a graphene-based long fiber comprising chemically functionalized graphene sheets that are chemically bonded with one another having an inter-planar spacing d.sub.002 from 0.36 nm to 1.5 nm as determined by X-ray diffraction and a non-carbon element content of 0.1% to 40% by weight, wherein the functionalized graphene sheets are substantially parallel to one another and parallel to the fiber axis direction and the fiber contains no core-shell structure, have no helically arranged graphene domains, and have a length no less than 0.5 cm and a physical density from 1.5 to 2.2 g/cm.sup.3. The graphene fiber typically has a thermal conductivity from 300 to 1,600 W/mK, an electrical conductivity from 600 to 15,000 S/cm, or a tensile strength higher than 1.0 GPa.

Provided is a graphene-based long fiber comprising chemically functionalized graphene sheets that are chemically bonded with one another having an inter-planar spacing d.sub.002 from 0.36 nm to 1.5 nm as determined by X-ray diffraction and a non-carbon element content of 0.1% to 40% by weight, wherein the functionalized graphene sheets are substantially parallel to one another and parallel to the fiber axis direction and the fiber contains no core-shell structure, have no helically arranged graphene domains, and have a length no less than 0.5 cm and a physical density from 1.5 to 2.2 g/cm.sup.3. The graphene fiber typically has a thermal conductivity from 300 to 1,600 W/mK, an electrical conductivity from 600 to 15,000 S/cm, or a tensile strength higher than 1.0 GPa.

A fire retardant material comprising a carbon fiber which tensile elasticity is 700 GPa or more, and a fire retardant resin such as polycarbonate.

A fire retardant material comprising a carbon fiber which tensile elasticity is 700 GPa or more, and a fire retardant resin such as polycarbonate.