Multilayer γ-Graphyne as Advanced Anode Materials—A First-Principles Study for Next Generation Batteries

The growing demand for sustainable green energy solutions has not only catalyzed the commercial success of lithium-ion batteries but also spurred investigations into abundant, earth-stored sodium-ion and multivalent magnesium-ion batteries as feasible alternatives. However, conventional lithium-ion batteries, which employ graphite anodes, exhibit structural instabilities due to delamination during charge/discharge cycles, thus limiting their application in demanding environments like electric vehicles and aircraft that require long-term cycle stability.<br/><br/>Emerging anode materials for rechargeable lithium-ion batteries are being evaluated based on key characteristics such as lower operational potentials relative to lithium, high storage capacities, structural reliability, and enhanced electrical conductivity—traits that are crucial for improving the electrochemical performance of batteries. In this context, γ-graphyne (γ-GY) has emerged as a promising material. This structure was first postulated by Baughman et al. in 1987, based on an acetylenic linkage that replaces one-third of the C-C bonds in graphite with sp² hybridized carbon bonds. The subsequent years have seen continuous innovations and enhancements in the bulk synthesis of γ-GY.<br/><br/>Despite the limited research in energy storage applications, the unique properties of γ-GY make it a potent candidate for such applications. Direct application of monolayer GY to larger ionic radii such as Na/Mg presents challenges due to significant volumetric expansion during the intercalation process. Against this backdrop, this study extends to explore the impact of multilayer γ-GY on the adsorption of Li/Na/Mg ions, considering the effects of layer stacking configurations (AAA, ABA, ABC) and the modification of materials with N and Si atom doping.