RESUMO
A novel type of ionic covalent organic framework (ICOF), which contains sp(3) â hybridized boron anionic centers and tunable countercations, was constructed by formation of spiroborate linkages. These ICOFs exhibit high BET surface areas up to 1259â m(2) g(-1) and adsorb a significant amount of H2 (up to 3.11â wt %, 77â K, 1â bar) and CH4 (up to 4.62â wt %, 273â K, 1â bar). Importantly, the materials show good thermal stabilities and excellent resistance to hydrolysis, remaining nearly intact when immersed in water or basic solution for twoâ days. The presence of permanently immobilized ion centers in ICOFs enables the transportation of lithium ions with room-temperature lithium-ion conductivity of 3.05×10(-5) â S cm(-1) and an average Li(+) transference number value of 0.80±0.02. Our approach thus provides a convenient route to highly stable COFs with ionic linkages, which can potentially serve as absorbents for alternative energy sources such as H2, CH4, and also as solid lithium electrolytes/separators for the next-generation lithium batteries.