Provided herein are nanofibers comprising carbon precursors, nanofibers comprising carbon matrices, and processes for preparing the same. In specific examples, provided herein are high performance lithium ion battery anodic nanofibers comprising non-aggregated silicon domains in a continuous carbon matrix.

A method of producing carbon fibers includes the step of providing polyacrylonitrile precursor polymer fiber filaments. The polyacrylonitrile precursor filaments include from 87-97 mole % acrylonitrile, and less than 0.5 mole % of accelerant functional groups. The filaments are no more than 3 deniers per filament. The polyacrylonitrile precursor fiber filaments can be arranged into tows of at least 150,000 deniers per inch width. The arranged polyacrylonitrile precursor fiber tows are stabilized by heating the tows in at least one oxidation zone containing oxygen gas and maintained at a first temperature T1 while stretching the tows at least 10% to yield a stabilized precursor fiber tow. The stabilized precursor fiber tows are carbonized by passing the stabilized precursor fiber tows through a carbonization zone. Carbon fibers produced by the process are also disclosed.

Process for manufacturing carbon fibers, includes a first spinning step of a fiber of PAN precursor and a second oxidation/carbonization step of the fiber and the plant thereof. The spinning and oxidation/carbonization steps are performed directly in line and continuously, and hence without any stocking buffer area of a PAN precursor between the two steps. The spinning step is performed at low speed, so that the output speed from the spinning step, downstream of the stretching operations, is a speed falling within the range of the suitable processing speeds in the subsequent oxidation/carbonization step. Moreover, the spinning step is performed in a modular way on a plurality of spinning modules aligned in one or more rows, each spinning module having a productivity not above 10% of the overall productivity of the spinning step. In any individual spinning module, the fibers downstream of the spinning area follow zig-zag, rectilinear paths.

A continuous carbonization method for the carbonization of a continuous, oxidized polyacrylonitrile (PAN) precursor fiber, wherein the precursor fiber exiting the carbonization system is a carbonized fiber which has been exposed to an atmosphere comprising 5% or less, preferably 0.1% or less, more preferably 0%, by volume of oxygen during its passage from a high temperature furnace to the next high temperature furnace. In one embodiment, the carbonization system includes a pre-carbonization furnace, a carbonization furnace, a substantially air-tight chamber between the furnaces, and a drive stand carrying a plurality of drive rollers that are enclosed by the air-tight chamber.

An example oven for heating fibers includes a chamber having upper and lower portions and a supply structure between first and second ends of the chamber, wherein the supply structure is in communication with a first heating system and is configured to direct first heated gas from the first heating system into the upper portion of the chamber to heat fibers in the upper portion at a first temperature, and wherein the supply structure is in communication with a second heating system and is configured to direct second heated gas from the second heating system into the lower portion of the chamber to heat fibers in the lower portion at a second temperature different than the first temperature such that the upper and lower portions of the chamber maintain the different temperatures without a physical barrier between the upper and lower portion.

One embodiment is directed to an oven for heating fibers. The oven comprises a plurality of walls forming a chamber and a supply structure disposed within the chamber between first and second ends of the chamber. The supply structure is in communication with a first heating system and is configured to direct heated gas from the first heating system into a first portion of the chamber. The supply structure is in communication with a second heating system and is configured to direct heated gas from the second heating system into a second portion of the chamber.

A heating device for producing carbon fibers from a thread-shaped fiber starting material, wherein the heating device has a central tubular induction heating element through which the fiber starting material is moved. The tubular induction heating element is surrounded by thermal insulation. At least one mid- to high-frequency induction coil is provided outside the thermal insulation, and an inert gas flows through the central induction heating element, in particular, for carbonizing and/or graphitizing the fiber starting material. For energy optimization, a first and a second tube element is provided on the outer side of the thermal insulation. The elements are made of material that is transparent to the induction field of the mid- to high-frequency induction coil and are spaced apart from one another by an annular gap through which the inert gas flows.

A process for preparing a carbon fiber precursor is hereby disclosed, wherein the precursor is selected from a series of solid PAN (polyacrylonitrile) fibers, wherein each member of the series contains about 0.5 mole % to about 8 mole % ammonium salt of 2-acrylamido-2-methyl propane sulfonic acid.

A heat treatment tooling fixture arrangement includes a male die and a female die. The female die includes a plurality of alignment surfaces and the male die includes a plurality of alignment rods configured to ride along the alignment surfaces to control motion of the male die with respect to the female die along two orthogonal directions (e.g., longitudinally and vertically). As an OPF preform shrinks during heat treatment (e.g., carbonization), the male die can move along a first axis toward the female die and can simultaneously move along a second axis along the female die to maintain compressive forces on the OPF preform.