Reconciling Mass Loading and Gravimetric Performance of MnO₂ Cathodes by 3D-Printed Carbon Structures for Zinc-Ion Batteries

To promote the real application of zinc-ion batteries (ZIBs), reconciling the high mass loading and gravimetric performance of MnO2 electrodes is of paramount importance. Herein, the rational regulation of 3D-printed carbon microlattices (3DP CMs) enabling an ultrathick MnO2 electrode with well-maintained gravimetric capacities is demonstrated. The 3DP CMs made of graphene and carbon nanotubes (CNTs) are fabricated by direct ink 3D printing and subsequent high-temperature annealing. 3D printing enables a periodic structure of 3DP CMs, while the thermal annealing contributes to high conductivity and defective surfaces. Due to these structural merits, uniform electrical field distribution and facilitated MnO2 deposition over the 3DP CMs are permitted. The optimal electrode with MnO2 loaded on the 3DP CMs can achieve a record-high specific capacity of 282.8 mAh g(-1) even at a high mass loading of 28.4 mg cm(-2) and high ion transfer dynamics, which reconciles the loading mass and gravimetric performance. As a result, the aqueous ZIBs based on the 3DP CMs loaded MnO2 afford an outstanding performance superior to most of the previous reports. This study reveals the essential role of interaction between active materials and current collectors, providing an alternative strategy for designing high-performance energy storage devices.