The cell wall of archaea is composed of S-layers and lack peptidoglycan molecules with the exception of methanobacteria who have pseudopeptidoglycan in their cell wall.
Source: Boundless. “Cell Walls of Archaea.” Boundless Microbiology. Boundless, 21 Jul. 2015. Retrieved 02 Nov. 2015 from https://www.boundless.com/microbiology/textbooks/boundless-microbiology-textbook/cell-structure-of-bacteria-archaea-and-eukaryotes-4/cell-walls-of-prokaryotes-34/cell-wall