Phase change-mediated core-sheath 3D printing of hollow microlattice pseudocapacitive aerogel electrode with favorable electrochemical properties

Abstract

Channel-interconnected regulation within 3D-printed pseudocapacitive electrode architecture to generate high active material loading/utilization and fast ion transport is pivotal but challenging for implementing high-performance pseudocapacitance system. Herein, we demonstrated an innovative phase change-mediated core-sheath direct ink writing (DIW) 3D printing strategy for controllably constructing pseudocapacitive hollow-microlattice graphene/NiCo₂O₄ aerogel (HGNA) electrode, with regular hollow channels in printed filaments and abundant well-interconnected hierarchical pores built by jointing tortuous pseudocapacitive graphene nanosheets. The unique architectural features facilitated highly efficient diffusion and infiltration of substance throughout the entire thick filaments from both “interior-exterior” and “exterior-interior” directions, thereby enabling high-level yet effective loading of active materials as well as unimpeded ion transport across the printed bulk-structured electrode. Kinetics analysis revealed that the capacitance of pseudocapacitive HGNA electrode was primarily contributed from fast kinetic process. An asymmetric device assembled with DIW-printed HGNA electrode boasted a high energy storage performance with capacitance of 3.43 F cm⁻² and energy density of 1.01 mWh cm⁻², while featuring remarkable cycling stability (87% after 8000 cycles) and superior capacity even at large electrode thickness. This work opens a promising route for processing rational pseudocapacitive electrode architectures toward high-capacity, fast-kinetics devices.