rC14: engineering a new dual-function carbon allotrope for sustainable energy technologies under conventional and micro-strain conditions

Abstract

The depletion of fossil fuels and increasing greenhouse gas emissions underscore the urgent need for sustainable energy technologies. Herein, we present rC14, a novel two-dimensional (2D) carbon allotrope engineered by reconfiguring graphene through carbon–carbon bond rotation and defect introduction, which exhibits remarkable multifunctionality for energy storage and conversion applications under conventional and micro-strain conditions. Theoretical calculations indicate that rC14 exhibits excellent dynamical, thermal and mechanical stability. Its high porosity facilitates a theoretical Na-ion storage capacity of 1115 m Ah g⁻¹, approximately three times higher than that of conventional graphite, and this high capacity is retained under small compressive strains. It possesses a low ion diffusion barrier (0.22–0.54 eV) that promises rapid charge/discharge kinetics. Furthermore, the non-uniform charge distribution across rC14, particularly at C1 and C2 sites, renders it an effective metal-free catalyst for the hydrogen evolution reaction (HER). The application of small biaxial compressive strains further refines the electronic structure and adsorption properties of the metal-free catalyst, yielding near-optimal ΔG_H* values (|ΔG_H*| around 0.05 eV) that surpass the values of conventional catalysts such as the Pt(111) surface (−0.09 eV). This work establishes rC14 as a promising dual-function metal-free material for next-generation energy storage and conversion systems under conventional and micro-strain conditions and demonstrates the effectiveness of the designed strategies in advancing material performance.