Advanced Co3O4/CeO2 Ink for 3D Printing Layered Porous Electrodes to Boost Energy Density of Solid-State Supercapacitor

Abstract

The electrochemical properties are influenced by the surface-active sites and the porosity of materials in solid-state asymmetric supercapacitor (SSASC) devices. Transitioning from two-dimensional (2D) bulk to three-dimensional (3D)-printed electrodes for high-performance in SSASCs remains both exciting and challenging. This work, for the first time, introduces a novel oxygen-rich Co₃O₄/CeO₂ nanocomposite (CCNC) ink with optimized rheological properties for constructing vertically aligned (3-layer and 5-layer) direct ink writing (DIW) 3D-printed SSASC electrodes with porous architectures. The 3D-printed 5-layer CCNC (3DP-5LCCNC) device demonstrates a remarkable mass loading of 18.61 mg cm⁻², achieving an excellent areal capacitance of 7.09 F cm⁻². The areal capacitance of 3DP-5LCCNC is ≈8.7 times greater than that of bulk CCNC (0.82 F cm⁻²) and 1.47 times higher than that of 3DP-3LCCNC (4.8 F cm⁻²). Furthermore, the 3DP-5LCCNC electrode exhibits an exceptional areal energy density of 2.366 mWh cm⁻², significantly surpassing the bulk (0.273 mWh cm⁻²) and 3DP-3LCCNC (1.626 mWh cm⁻²) devices. This enhancement is attributed to the vertically aligned porous architecture, facilitating ion transport and enhances kinetic reactions. This work presents an innovative approach to ink formulation and provides a framework for designing high-performance 3D-printed electrodes with rapid ion transportation and outstanding electrochemical properties for advanced energy storage devices.