Thermal shielding device, materials, and methods thereof

A thermal shielding device comprising:

• i. a first metal layer;
• ii. a second metal layer;
• iii. a core layer (preferably an expandable core layer) interposed between the first metal layer and the second metal layer;
• and
• iv. a barrier layer that provides a thermal barrier (e.g. thermal insulation), an electrical barrier (e.g., electrical insulation), or both;
• optionally wherein the thermal shielding device has a thermal conductivity of about 0.015 to about 4 W/mK, and upon heating to a temperature of about 100° C. or more, the core layer causes a separation distance between the first and second metal layers to increase in one or more regions and a thickness of the thermal shielding device to increase by about 15 percent or more in the one or more regions.