A thermal barrier component for an electrochemical cell (e.g., a battery) includes a mat, a functional material, and a polymer binder. The mat includes a porous matrix. The functional material is in pores of the porous matrix. The functional material includes an oxide. In certain aspects, the functional material may be a composite material. The polymer binder is in contact with the porous matrix and the functional material. At least one of the porous matrix, the functional material, and the polymer binder is configured to serve as an intumescent carbon source. The oxide is configured to catalyze thermal degradation of the intumescent carbon source to form intumescent carbon at a first temperature. The first temperature is greater than or equal to about 300° C. The thermal barrier component is configured to mitigate thermal runaway in an electrochemical cell. The thermal barrier component may include one or more layers.