Experimental and molecular dynamics investigation on thermal safety: oxidation mechanism of graphyne type materials

Graphyne (GY), a novel type of nano carbon allotrope, exhibits a unique sp1- and sp2- hybridisation, forming “ −  − C C ” acetylene linkage(s) between two adjacent sp2- hybridised carbon benzene rings. Graphdiyne (GDY), as the first synthesised GY variant, has demonstrated exceptional energy storage properties, providing the potential for next-generation high-performance battery anodes. However, safety concerns regarding graphdiyne-type materials’ thermal stability and combustibility must be addressed before their utilisation in energy storage applications. This research aims to unveil the fundamental thermal safety aspect of graphdiyne type materials, explicitly focusing on characterising the thermal oxidation mechanism. A hybrid approach combines experimental and numerical methods to investigate materials’ behaviours. The experimental approach extracts primary reaction kinetic parameters for benchmarking. Subsequently, with the inclusion of graphene for comparison purposes, molecular dynamics simulations are employed to replicate variant morphologies of carbon nano allotropes and investigate the details of the decomposition mechanism at the atomic level. The research outcomes demonstrate that graphene and graphdiyne undergo different decomposition mechanisms during oxidation, and the acetylene chain length drastically affects the pyrolysis kinetics for graphdiyne family materials. Although they do not exhibit exceptional graphene properties, graphdiyne family materials still have better stability than most composite polymers in battery electrodes. This research represents the first comprehensive investigation of the thermal decomposition mechanism between carbon nano allotropes, which addresses fire safety concerns and enhances the potential of graphdiyne for high-performance energy storage. Additionally, this study guides the evaluation of alternative carbon nanomaterials in future developments.