A composite fiber includes a core comprising a MXene polymer fiber with MXene distributed as stacked nanosheets within a first polymer, a first coating layer of benzoic acid-based organic molecules on the MXene polymer fiber, a second polymer in fiber form on the first coating layer, and a second coating layer of a thermoplastic polymer with a thermal strain of about 80 C. or higher. The method for manufacturing the composite fiber involves mixing MXene and a first polymer, depositing a first coating layer, plying and twisting with a second polymer, and applying a second coating layer. The first polymer may include polyacrylonitrile (PAN), and the second polymer may include materials such as nylon or polyethylene terephthalate (PET). The process includes steps such as wet spinning and surface treatment at high temperatures.

A composite fiber includes a core comprising a MXene polymer fiber with MXene distributed as stacked nanosheets within a first polymer, a first coating layer of benzoic acid-based organic molecules on the MXene polymer fiber, a second polymer in fiber form on the first coating layer, and a second coating layer of a thermoplastic polymer with a thermal strain of about 80 C. or higher. The method for manufacturing the composite fiber involves mixing MXene and a first polymer, depositing a first coating layer, plying and twisting with a second polymer, and applying a second coating layer. The first polymer may include polyacrylonitrile (PAN), and the second polymer may include materials such as nylon or polyethylene terephthalate (PET). The process includes steps such as wet spinning and surface treatment at high temperatures.