Planar net-τ: A new high-performance metallic carbon anode material for lithium-ion batteries

Abstract

Based on first-principles calculations, we propose a new two-dimensional (2D) carbon allotrope (net-τ), which consists of quadrilateral, pentagonal, hexagonal, octagonal and decagonal rings. Our results demonstrate that the net-τ is a dynamically stable phase with intrinsic metallicity. Remarkably, it is found that the maximum theoretical capacity of the net-τ reaches 558 mAh g−1 on one side, which is 1.6 times that of commercial graphite and recently predicted ψ-graphene (372 mAh g−1). Meanwhile, the net-τ has a relatively low diffusion energy barrier (0.296 eV) and open-circuit potential (0.039 V), which shows its good potential as an anode material for lithium-ion batteries. Equally important, the net-τ may be synthesized by a bottom-up scheme through multiple intermediate reactions with benzocyclobutene and fulvalene. These interesting findings not only increase the family of two-dimensional metallic carbon allotropes, but also provide a novel strategy to realize high-performance anode materials by designing a 2D structure with high-order carbon rings.