Lithium Intercalation in Covalent Organic Frameworks: A Porous Electrode Material for Lithium-Ion Batteries

Increasing global energy demand urgently requires a sustainable energy storage device. Lithium-ion battery (LIB) technology has gathered wide attention toward the development of reliable, efficient, and sustainable energy storage systems. Despite all these advantages, designing an electrode material of LIBs with large cycle life, high specific capacity, and rate performance all at the same time remains a major challenge. Very recently, covalent organic frameworks (in short COFs) have attracted immense attention as an electrode material for efficient Li storage in a LIB due to their incredibly diverse and tunable structures. Here, we have studied a highly porous and semiconducting COF, i.e., COF-IITI-0, as an electrode material for the storage of Li atoms in a LIB. A hybrid periodic density functional theory (DFT) method has been implemented to investigate the Li intercalation mechanism, framework and electronic properties, and its theoretical capacity and average voltage. We report the lithium atom intercalation in the pristine COF-IITI-0 material consisting of maximum active groups (C6H4, C3N3, BO2C2) when it is used as electrode materials for LIBs. It has the highest capacity among the most polymer-based electrode materials so far. For the highest amount of lithium (up to 10 Li) atoms intercalated in the unit cell of the pure COF-IITI-0, it has been computationally predicted that the material would have a large theoretical capacity of 369 mAh g–1 with the highest average voltage about 4.8 eV. Therefore, we can say that the pristine COF-IITI-0 porous COF may be an auspicious effective electrode material for LIBs with such superior capacity and cell voltage. This work lays the foundation for future experimental exploration of Li-intercalated COFs for Li storage applications.