First-Principles Investigation of Li⁺-Doped Conjugated Microporous Polymer as a Potential Hydrogen Storage Medium

Abstract

Abstract:We used first-principles calculations to investigate the adsorptive binding of hydrogen molecule with lithium doped triethynylbenzene. The prior binding site of Li + is above the C≡C triple bond rather than the aromatic ring at the computational level of UM06-L/6-311G(d,p), which could provide an accurate description of cation-π interaction. For single, double, and multiple dihydrogen interaction with a formula unit of Li + -doped triethynylbenzene, the average binding energies per H2 are found to be in the range of -5.08 ~ -4.58 kcal/mol. The strong binding affinity is promising for hydrogen storage, since it will play a crucial role in physisorption at ambient condition.Further, with a saturated 4-5-5 adsorption, a reversible hydrogen storage capacity of 14.0 wt% is attained. Based on the calculated results, we designed Li cation doped conjugated microporous polymer as hydrogen storage medium and obtained excellent hydrogen uptake performance.