3D printed rGO/CNT microlattice aerogel for a dendrite-free sodium metal anode

Uncontrolled dendrite formation induces inferior electrochemical performance in sodium metal and even severe safety issues, resulting in metallic sodium anode being unsuitable for practical applications. Herein, an artificial reduced graphene oxide/carbon nanotube (rGO/CNT) microlattice aerogel was constructed using three-dimensional (3D) printing technology and further adopted as a sodium metal host. With its specially designed architecture, the 3D rGO/CNT microlattice aerogel can effectively reduce the local current density and provide abundant active nucleation sites, resulting in homogeneous sodium deposition to overcome the issue of dendrite formation. As a result, the Na@rGO/CNT microlattice anode enables an areal capacity of 1 mA h cm⁻²at 2 mA cm⁻²with a small nucleation overpotential of 17.8 mV, with a stable cycling performance for 640 cycles at a high current density of 8 mA cm⁻². The experimental and simulation results show that the improved performance can be attributed to the rational design of the hierarchical rGO/CNT microlattice aerogel with tuned surface kinetics. Finally, a full battery using a 3D Na@rGO/CNT microlattice as an anode was assembled and delivered a capacity of 67.6 mA h g⁻¹at 100 mA g⁻¹after 100 cycles. Our results demonstrate that the 3D printed rGO/CNT microlattice aerogel is a promising candidate as a sodium metal host for future generation of sodium metal batteries.