The cooperative cation– π interaction in two-dimensional THD-C as a high-capacity anode material for Li-ion batteries

Two-dimensional (2D) carbon allotropes for high-performance electrode materials in lithium-ion batteries (LIBs) are attracting a great deal of research interest due to their unique architectures. Herein, we perform the first-principles calculations to systematically investigate the feasibility of 2D sp–sp2 hybridized THD-C (tetra-, hexa-, and dodeca-membered rings), as a potential anode for LIBs. Our simulations indicate that two spatially adjacent acetylenic bonds engender a modest Li–C coupling via the cooperative cation–π interaction driven by partial electron transfer, which exhibits a suitable Li adsorption energy of –0.78 eV. 2D THD-C is proven to be a favorable anode material that offers a high theoretical capacity (1116.7 mAh/g), a low Li diffusion barrier (0.49 eV), and a moderate open-circuit voltage (0.40 V). Furthermore, it retains a small volume change (∼3%) as well as favorable structural and thermal stability even at maximum Li concentration. Overall, those findings not only provide an in-depth mechanistic insight but also extend an effective method to search for high-performance anode materials in advancing LIB technology.