Structural Design and Manufacturing of Three-Dimensional Porous Superstructures with Additive and Subtractive Electrochemistry for Flexible Self-Powered Electronics and Electromechanical Devices*

The recent search for advanced materials with desired properties for the next-generation flexible energy and electronics has been focused on the unique class of three-dimensional (3D) porous superstructures made of 2D materials, such as graphene, graphite, and molybdenum disulfide.
In this work, we report an innovative and rational approach to create 3D metallic foams with tunable multi-level porosity by using a process consisting of an additive electrodeposition and subtractive electroetching. The resulted metallic foams can readily serve as catalytic templates for the growth of 3D hierarchically porous thin graphite. The 3D graphite is freestanding after selective etching of the metallic template. They provide enhanced mechanical properties and electrochemical performances when applied as supercapacitor electrode supports. They can be readily integrated with our wearable GF/polymer strain sensors developed recently and nanomotor manipulation systems into self-powered sensing and electromechanical devices, respectively.