3D Structural Strengthening Urchin-Like Cu(OH)₂-Based Symmetric Supercapacitors with Adjustable Capacitance

Developing advanced three-dimensional (3D) structural supercapacitors with both high capacity and good mechanical strength remains challenging. Herein, a novel road is reported for fabricating 3D structural strengthening supercapacitors with adjustable capacitance based on urchin-like Cu(OH)₂ lattice electrodes by bridging 3D printing technology with a facile electroless plating and electro-oxidation method. As revealed by the results, the 3D-printed octet-truss lattice electrode features a high volumetric capacitance of 8.46 F cm⁻³ at 5 mA cm⁻³ and superior retention capacity of 68% at 1 A cm⁻³. The assembled symmetric supercapacitor with a 70.2% capacitance retention after 5000 cycles possesses a 12.8 Wh kg⁻¹ energy density at a power density of 2110.2 W kg⁻¹. Additionally, the resulting 3D structural strengthening electrodes can achieve both high compressive strength and toughness of 30 MPa and 264.7 kJ m⁻³, respectively, demonstrating high mechanical strength and excellent antideformation capacity. With the proposed strategy, the electrochemical and mechanical properties of these novel 3D structural strengthened supercapacitors can be easily tuned by a simple spatial framework design, fulfilling the increasing demand of highly customized power sources in the space-constrained microelectronics and astronautic electronics industries.