3D-Printed Hierarchically Porous MOF-Derived Cathodes for Realizing High-Performance Flexible Quasi-Solid-State Aqueous Zinc–Cobalt Batteries

Rechargeable aqueous Zn-ion batteries hold significant promise for wearable electronics due to their intrinsic safety and eco-friendliness, yet cobalt-based cathodes remain constrained by poor conductivity and sluggish kinetics. Addressing these limitations, we developed 3D-printed (3DP) hierarchically porous MOF-derived cathodes for aqueous zinc-cobalt (Zn-Co) batteries via three synergistic innovation technology pathways: (i) ZIF-67-derived nitrogen-doped carbon-coated Co3O4 nanoparticles (Co3O4-NC NPs) were synthesized using a scalable hydrothermal method and subsequent annealing process; (ii) a dual-ion (Zn2+/Mn2+)-optimized hybrid electrolyte system, that is, the dual-ion synergy from Mn2+ additive enhanced Zn2+ desolvation kinetics while suppressing dendrite formation; and (iii) 3D printing hierarchically porous microlattice architecture integrating reduced graphene oxide/carbon nanotubes-based (rGO/CNTs-based) to establish bicontinuous ion/electron transport networks. The 3DP button Zn-Co cells (thickness: 0.8 mm) delivered an exceptional areal capacity (∼0.30 mAh cm-2 at 2 mA cm-2) and excellent cycling stability (near-zero decay over 750 cycles). Specially, a 4 mm thick 3DP flexible quasi-solid-state Zn-Co battery (3DP f-QSS Zn-Co) device employing PVA/(ZnSO4 + MnSO4) gel electrolyte achieved an enhanced areal capacity (∼0.16 mAh cm-2 at 1 mA cm-2), a high energy density (∼151.0 Wh kg-1 at a power of 975 W kg-1), and an ultralong cyclability (∼87.5% retention after 2500 cycles at 1 A g-1). Furthermore, the 3DP f-QSS Zn-Co devices enabled scalable voltage output through a series integration, successfully powering high-power LEDs and miniature motors. This work introduced an MOF-derived hierarchical porous architecture synergistically integrated with advanced 3D printing, enabling the development of high-performance 3DP-f-QSS Zn-Co batteries specifically engineered for next-generation wearable electronic systems.