Lithium-Induced Covalent Organic Frameworks with Enhanced Sorption Heat for Efficient Hydrogen Storage

Covalent organic frameworks (COFs) possess high surface areas and tunable pore structures and are promising candidates for H 2 physisorption materials. However, their interaction with H 2 molecules is too weak to take advantage of the high porosity of the COFs. Here, we report the first example of metal-doped enhanced H 2 -physisorption COF. By leveraging the superior stability of TPB-DMTP-COF, we can well preserve the porosity of the COF after lithium (Li) doping, yielding a surface area of 1350 m 2 /g. Due to the Li-doping-enhanced H 2 isosteric heat, the material’s total H 2 uptake increased from 4.98 to 6.91 wt % at 77 K and 80 bar. The Li-doping-induced enhancement effect does not involve chemisorption, and the material shows excellent cycling performance: 10 cycles at 30 bar with a capacity retention of 99%. Our results reveal that tuning H 2 adsorption heat by postmodification is a promising strategy to exploit the potential of porous materials for efficient H 2 storage.