Polymer electrolyte (PE) that possesses improved thermal and mechanical stability is believed to be by far one of the most promising electrolytes for meeting the safety and performance needs of advanced electrochemical devices. Here, high-performance PEs are fabricated via facile thiol-Michael addition catalyzed by triethylamine in the presence of lithium salts. The lithium salt functions as both an ion source and a co-catalyst, significantly accelerating the thiol-Michael addition reaction. The PEs exhibit a superior thermal decomposition temperature up to 300 degrees C. Additionally, PEs from the thiol-decorated polyhedral oligomeric silsesquioxane display reversible electrochemical response and stable cycling performance. Our findings based on a self-catalyzed strategy provide a promising direction for rapidly fabricating PEs that meet electrochemical requirements for practical solid polymer batteries.