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Carbon is one of the most important materials extensively used in industry and our daily life. Crystalline carbon materials such as carbon nanotubes and graphene possess ultrahigh strength and toughness. In contrast, amorphous carbon is known to be very brittle and can sustain little compressive deformation. Inspired by biological shells and honeycomb-like cellular structures in nature, we introduce a class of hybrid structural designs and demonstrate that amorphous porous carbon nanospheres with a thin outer shell can simultaneously achieve high strength and sustain large deformation. The amorphous carbon nanospheres were synthesized via a low-cost, scalable and structure-controllable ultrasonic spray pyrolysis approach using energetic carbon precursors. In situ compression experiments on individual nanospheres show that the amorphous carbon nanospheres with an optimized structure can sustain beyond 50% compressive strain. Both experiments and finite element analyses reveal that the buckling deformation of the outer spherical shell dominates the improvement of strength while the collapse of inner nanoscale pores driven by twisting, rotation, buckling and bending of pore walls contributes to the large deformation.

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Architected 2D structures are of growing interest due to their unique mechanical and physical properties for applications in stretchable electronics, controllable phononic/photonic modulators, and switchable optical/electrical devices; however, the underpinning theory of understanding their elastic properties and enabling principles in search of emerging structures with well-defined arrangements and/or bonding connections of assembled elements has yet to be established. Here, we present two theoretical frameworks in mechanics-strain energy-based theory and displacement continuity-based theory-to predict the elastic properties of 2D structures and demonstrate their application in a search for novel architected 2D structures that are composed of heterogeneously arranged, arbitrarily shaped lattice cell structures with regulatory adjacent bonding connections of cells, referred to as heterogeneously architected 2D structures (HASs). By patterning lattice cell structures and tailoring their connections, the elastic properties of HASs can span a very broad range from nearly zero to beyond those of individual lattice cells by orders of magnitude. Interface indices that represent both the pattern arrangements of basic lattice cells and local bonding disconnections in HASs are also proposed and incorporated to intelligently design HASs with on-demand Young's modulus and geometric features. This study offers a theoretical foundation toward future architected structures by design with unprecedented properties and functions.

Graphene is considered as an ideal material candidate for next‐generation electronic devices due to its high carrier mobility while the associated thermal management has become a critical barrier. Designing graphene whose thermal transport properties can be tuned through external fields is highly desired. Here, an auxetic graphene (AG) and a contractile graphene (CG) are created and a conceptual design of thermal controllable graphene heterostructures is demonstrated by tailoring them together. Using computational simulations, it is shown that the thermal conductivity of graphene heterostructures can be regulated by patterning AG and CG unit cells with different interface properties under a uniaxial tensile strain. Analyses of both mechanical deformation and vibrational spectra indicate that the thermal transport properties of graphene heterostructures are highly dependent on their mechanical stress distribution, and also rely on the interfaces that are parallel with the directions of mechanical loadings. Theoretical models that integrate the contributions of mechanical loading and patterned‐interfaces are developed to quantitatively describe the thermal conductivity of graphene heterostructures. Good agreement of thermal conductivity between theoretical predictions and extensive simulations is obtained. These designs and findings are expected to pave a new route to seek interface‐mediated stretchable thermal electronics with mechanically controllable performance.