Mechanically Assembled, Three-Dimensional Hierarchical Structures of Cellular Graphene with Programmed Geometries and Outstanding Electromechanical Properties.

Three-dimensional (3D) cellular graphene structures have wide applications in energy storage, catalysis, polymer composites, electromagnetic shielding, and many others. However, the current strategies to form cellular graphene are only able to realize limited structure control and are hard to achieve the construction of 3D hierarchical architectures with complex, programmed configurations, limiting the design capabilities to satisfy various next-generation device applications. In addition, cellular graphene usually exhibits limited electromechanical properties, and its electrical and electrochemical performances are dramatically affected by mechanical deformations, constraining its applications in emerging wearable electronics and energy devices. Herein, we report a simple, general, and effective route to 3D hierarchical architectures of cellular graphene with desired geometries through the use of a mechanically guided, 3D assembly approach to overcome the aforementioned two challenges. Demonstrations include more than 10 3D hierarchical architectures with diverse configurations, ranging from mixed tables and tents, to double-floor helices, to kirigami/origami-inspired structures, and to fully separated multilayer architectures. The LED arrays interconnected with 3D helical coils and 3D interdigital supercapacitors fabricated with solid-state electrolytes provide prototypic examples of wearable devices that exhibit outstanding electromechanical properties and can maintain stable performances with little change in the electrical and electrochemical responses under extreme deformations, in both the static and cyclic loading conditions.