Quantum Chemical Support on the Two-Dimensional Assembly of Porphyrin Rings in the Application of Energy-Storage Devices

Metal-ion batteries are the revolutionary gadgets of the present decade which still need improvement in efficiency and stability. Porphyrin, a common organic molecule, is considered in the present study for applications in solid-state physics. The organic molecule is covalently bonded to form a two-dimensional (2-D) sheet of covalent organic frameworks (COFs), and the stability and nature of the material are studied using density functional theory. We have investigated a 2-D sheet of porphyrin as an adsorbent for alkali metal ions, viz., Li⁺, Na⁺, and K⁺, using first principles study to be used as an electrode in batteries. The counterpoise method employed to investigate the adsorption of alkali metals at different sites of the porphyrin sheet (PS) shows that the Li⁺ ion has strong affinity toward the sheet at the N site with a maximum energy of 109.9 kcal/mol and that the ability of absorbing Li clusters is much higher than that of individual Li⁺ ions. The decrease in the highest occupied molecular orbital–lowest unoccupied molecular orbital gap confirms the strong affinity of alkali metals with the PS. The electron density difference plot establishes the charge accumulation and depletion on the PS when it interacts with alkali metals. The study detailed in the present manuscript strongly recommends porphyrin COFs as an electrode material for battery applications.