A novel thermal insulation coating with layer-by-layer stacked nanosheets towards ultralow thermal conductivity

Layered structures show low thermal conductivity in the out-of-plane direction. But layer-by-layer structures coatings are rarely reported for the thermal insulation applications due to the difficulty in preparation methods. It is feasible to prepare the layer-by-layer structures from 2D materials by nanotechnology. However, achieving high ordering of nanoceramic coatings and maintaining thermal stability of layered structures after solution processes remains a significant challenge. Herein, we first reported a strategy using electrospray deposition to prepare layer-by-layer nanosheet coatings. The obtained coatings exhibit a low out-of-plane thermal conductivity. After annealing at 800 degrees C, they show an ultra-low thermal conductivity of 0.07 W center dot m-1 center dot k-1 due to the nanopore structure. Furthermore, by doping large-sized metal ions, we improved the thermal stability of the layered structures from 600 degrees C to 800 degrees C. The Ca2Nb3O10 - nanosheet coatings also exhibit superior anti-corrosion and antioxidant abilities on zinc-coated iron, implying broad prospects for their application.