Net‐C18: A Predicted Two‐Dimensional Planar Carbon Allotrope and Potential for an Anode in Lithium‐Ion Battery

Abstract

Net‐C18, a predicted two‐dimensional (2D) graphene‐like carbon allotrope, is investigated via first‐principles calculations. Its space group is Pmmm. There are 18 carbon atoms per cell. Net‐C18 has five‐, six‐, and eight‐membered rings. Net‐C18 may be formed by adding even pairs of carbon atoms on the top of hexagons to reconstruct new five‐ and eight‐membered rings, extending the strategy of Haeckelite. Compared to that of graphene (−9.28 eV atom−1), the total energy of net‐C18 (−9.15 eV atom−1) is only 0.13 eV atom−1 higher, revealing that net‐C18 is energetically metastable. The calculations of phonon and ab initio molecular dynamics (AIMD) demonstrate dynamical and thermal stability of net‐C18. The independent elastic constants of net‐C18 meet the criterial for the mechanical stability of 2D structure. Its in‐plane stiffness along x or y axis is comparably large. The AIMD results reveal that net‐C18 has good thermal stability at 1500 K. The band structure also demonstrates that it is metallic. Furthermore, the diffusion of Li atoms on net‐C18 has a low energy barrier (0.32 eV), and net‐C18 has a low open‐circuit voltage (0.024 V) and a high theoretical specific capacity (403 mAh g−1). Thus, net‐C18 may provide high‐temperature resistant, flexible electrode in electronics and a promising metallic anode in lithium‐ion battery. The proposed formation of net‐C18 may open a new pattern defect for the designs of new carbon allotropes.

Self-Template Synthesis of Prussian Blue Analogue Hollow Polyhedrons as Superior Sodium Storage Cathodes

“…The goal of being “carbon neutral” has prompted researchers to seek new energy conversion and storage systems that possess greener, more cost-effective production processes, for instance, for wind energy, solar energy, and electrochemical energy storage and so on. Among them, sodium-ion batteries (SIBs) based on Prussian blue analogue (PBA) cathodes with open three-dimensional crystal structures, high Na + storage capacity, and low cost have attracted much attention. − …”

Adsorption and Detection of 2,4,6-Trinitrotoluene by New Two-Dimensional BCN Monolayers: A First-Principles Study

“…Graphene, as a well-known two-dimensional (2D) nanomaterial having excellent physical and chemical properties, has been explored globally in recent years, including optoelectronics, sensing, energy, biomedicine, and other fields. 1−7 The discovery of graphene has stimulated the exploration of 2D materials, and many graphene-like structures were found, 8−10 such as net-C18, 11 wrinkled graphene, 12 hp-C18, 13 and pentagraphene. 14 In addition, the gapless graphene can become semiconducting upon doping with other atoms to extend the investigations of graphene-like structures.…”

“…Graphene, as a well-known two-dimensional (2D) nanomaterial having excellent physical and chemical properties, has been explored globally in recent years, including optoelectronics, sensing, energy, biomedicine, and other fields. − The discovery of graphene has stimulated the exploration of 2D materials, and many graphene-like structures were found, − such as net-C18, wrinkled graphene, hp-C18, and penta-graphene . In addition, the gapless graphene can become semiconducting upon doping with other atoms to extend the investigations of graphene-like structures. − Due to their atomic sizes close to carbon’s, nitrogen and boron atoms are widely used as dopants to form boron carbon nitrogen (BCN) compounds. , Many BCN materials with unique structures and excellent performance have been developed. − A h-BCN material was synthesized by graphene and h-BN .…”

Two-Dimensional Planar BGe Monolayer as an Anode Material for Sodium-Ion Batteries

“…Perfect planar configurations have been viewed as a new class of potential candidates for the anode materials of LIBs and NIBs. The ab initio computations show that many planar 2D materials, such as NiC 3 monolayer and Net-C18, are potentially superior candidates for LIBs and NIBs. For example, Zhu et al identified a fully planar NiC 3 monolayer as a highly symmetric anode material, and the capacity for Li and Na reaches 1698 mAh g –1 .…”

“…For example, Zhu et al identified a fully planar NiC 3 monolayer as a highly symmetric anode material, and the capacity for Li and Na reaches 1698 mAh g –1 . Cai et al predicted a 2D graphene-like carbon allotrope of Net-C18 with a low energy barrier (0.32 eV), low open-circuit voltage (OCV; 0.024 V), and high theoretical specific capacity (403 mAh g –1 ) for LIBs. Although intensive investigations have been conducted, perfect planar structures with excellent performance are still under development in the area of NIBs.…”