(400c) Three-Dimensional Highly Compressible and Stretchable Conductors

There are many applications for deformable energy storage device, such as in wearable electronics, integrated surgical implants, and electrical systems with conformal formats. Electrodes are part of all electrochemical energy storage devices.  Thus, electrochemically active electrodes, specifically with stretchable, compressible, and bendable mechanical characteristics, are of great value in the development of these deformable devices.  However, current research has been confined mostly to systems of 2D configuration through the use of conducting materials printed onto an elastic 2D substrate, and extension into 3D structures through the use of easily scalable methods has not yet been achieved. Here we report an easily scalable method to fabricate a 3D elastomeric, electrically conducting, and electrochemically active material by coating an elastomeric foam with a thin reduced graphene oxide layer.  The material exhibits excellent durability in both mechanical and electrochemical performance with respect to repeated deformation cycling.  In addition, characterization of these materials shows that both the electrical resistance and gravimetric capacitance depend on the degree of compression and the thickness of the coated graphenic layer. SEM images show deformation of the conducting layer upon compression that is reversible after the first compression cycle.  Results are presented of capacitors with electrodes made with this material and the corresponding structural-property relationship.