3D‐Printed, Superelastic Polypyrrole–Graphene Electrodes with Ultrahigh Areal Capacitance for Electrochemical Energy Storage

Abstract Disruptive custom electronics require a transformation in energy storage systems from traditional thin‐film units to shape conformable 3D components. However, current thick electrodes suffer from uncontrollable geometries and architectures, which lead to ion diffusion limitations, and poor mechanical properties. Here, designed, superelastic polypyrrole (PPy)‐coated graphene aerogel (GA) electrodes are fabricated via 3D printing and polymer self‐assembly methods. This resilient GA template (up to 90% compression) can be printed into any desired shape including engineered 3D architectures with periodic macropores, which promote the uniform deposition and adhesion of PPy onto the support. The coated PPy thin film increases the specific gravimetric capacitance of the GA electrode from 14 to 395 F g⁻¹ with 90% retention after 5000 charging–discharging cycles. The capacitance remains the same value after 100 times compression cycles. It also improves the compressive strength by one order of magnitude from 0.14 to 2.4 MPa. Areal capacitance and energy density of the PPy–GA electrode are 2 F cm⁻² and 0.78 mWh cm⁻², respectively, which to the best of the knowledge break the record for compressible electrodes, respectively. This approach enables the fabrication of complex architectured energy storage modules with enhanced compressibility, ultrahigh areal electrochemical performance, and excellent cyclability.