One-step firing of cellulose fiber and ceramic precursors for functional electro-thermal composites

A conductive composite was designed and fabricated by combining cotton fibers and ceramic precursors (kaolin, feldspar and quartz) in a one-step firing process. The firing process achieved the carbonization of cotton fibers and ceramicization of inorganic precursors simultaneously under a nitrogen environment. The prepared cotton/ceramic composite materials exhibited significant electro-thermal effect and overload protection function. The obtained composite based on 64 single cotton yarns reached more than 100 °C at 10 V (0.518 A) after 20 s and showed reliable cyclic heating performance. Carbonized cotton showed better electro-thermal performance than rayon, which could reach a maximum temperature of 188 °C at 10 V (0.518 A) after 6 min. The composites could power-off automatically at a high voltage, which is useful for circuit breakers or high temperature protection device. Furthermore, the maximum temperature from electro-thermal conversion for the composites can be adjusted by controlling the operating voltage and cotton to rayon ratio. The great electro-thermal features and strong mechanical properties make the composite a good candidate for in-door temperature control.