APA-graphene: A multifunctional material for lithium-ion batteries and electrocatalytic water splitting

In Lithium-ion batteries (LIBs) and electrocatalytic water splitting, two promising technologies for future clean energy storage and regeneration, exploring electrode materials with excellent properties is critical for facilitating reaction kinetics and enhancing energy utilization efficiency. Starting from the successfully synthesized polyazulene carbon fragment, we designed a new two-dimensional (2D) carbon allotrope, anti-polyazulene graphene (APA-graphene). The robust stability of APA-graphene, along with the fact that nanoribbons of TPH-graphene and phagraphene have been successfully synthesized from 2,6-polyazulene chains, strongly indicate the high feasibility of experimental synthesis for APA-graphene. The metallic nature of APA-graphene, along with its distinctive anisotropic mechanical properties, which encompass the rare negative Poisson's ratios (-0.04 similar to -0.37 in all directions), has been predicted through first-principles calculations. It also shows high feasibility as an anode material for LIBs, with a large Li adsorption energy (-0.52 eV), low energy barrier for Li diffusion (0.25 eV), substantial maximum Li storage capacity (558 mAh/g), and low average open circuit voltage (0.16 V). Furthermore, APA-graphene demonstrates remarkable capability in the electrocatalytic dissociation of water molecules, with lower overpotentials for hydrogen and oxygen evolution reactions (0.04 and 0.83 V, respectively) compared to most known electrocatalysts. Overall, APA-graphene is a multifunctional material with exceptional performance, showcasing its great potential for applications in future clean energy technology.