Popgraphene: a new 2D planar carbon allotrope composed of 5–8–5 carbon rings for high-performance lithium-ion battery anodes from bottom-up programming

Abstract

Two-dimensional (2D) carbon allotropes have attracted great attention in both science and engineering fields. Their extraordinary and/or unique properties make them promising for engineering applications, ranging from metal-ion batteries to biosensors. Herein, by employing first-principles calculations, we propose a new 2D planar carbon allotrope, popgraphene, which is composed of 5–8–5 carbon rings. Using a bottom-up approach, popgraphene could be constructed via the formation of atomically precise 5–8–5 line defects in graphene by simultaneous electron irradiation. Popgraphene is intrinsically metallic. It has low energy and possesses great dynamic, thermal and mechanical stability. Our calculations also show that it has a high theoretical capacity for Li atoms (Li₄C₆: 1487 mA h g⁻¹), a low Li diffusion barrier (<0.55 eV), and a low average open circuit voltage (0.45 V). Such excellent characteristics suggest that programmable metallic popgraphene is a promising anode material for use in Li-ion batteries (LIBs) with fast charge/discharge rates. Our simulation results also indicate that van der Waals corrections play little role in the structural parameters of popgraphene, whereas they play a central role in the adsorption and diffusion abilities as well as the electrochemical performance of popgraphene. This study provides fundamental insight into the design of new materials with extraordinary properties for their excellent applications, including for the next generation of LIBs, and may open up a cutting-edge field in programming experimentally realized low-dimensional materials.