Enhanced Potassium Ion Diffusion and Interface Stability Enabled by Potassiophilic rGO/CNTs/NaF Micro-Lattice Aerogel for High-Performance Potassium Metal Batteries

Abstract

Potassium metal batteries (PMBs) are considered as a promising candidate for stationary energy storage devices owing to the abundant potassium resources, cost-effectiveness, and potential energy density. However, the practical application of PMBs is hindered by the uncontrolled K dendrite growth, severe volume variation, and unstable solid electrolyte interface (SEI) layer. Herein, a micro-lattice aerogel with hierarchical porous structure and high potassiophilicity composed of reduced graphene oxide (rGO), carbon nanotubes (CNTs), and sodium fluoride (NaF) is designed by 3D printing strategy (denoted as 3DP-rGO/CNTs/NaF) as the host for K metal anode. The hierarchical porous structure uniformizes K⁺ flux by establishing continuous transport channels, enhancing K⁺ transport kinetics. NaF reduces the nucleation barrier of K metal, promoting homogeneous K deposition and generating a robust SEI layer. As anticipated, the K||3DP-rGO/CNTs/NaF asymmetric batteries achieve stable cycling for 1750 cycles at 0.5 mA cm⁻²/0.5 mAh cm⁻² with an average Coulombic efficiency of 98.5%. When the 3DP-rGO/CNTs/NaF@K anode coupled with a perylene-3,4,9,10-tetracarboxylic dianhydride (PTCDA) cathode in full batteries delivers a reversible capacity of 107.4 mAh g⁻¹ with a capacity retention of 90.3% after 2000 cycles at 100C. This work presents an efficient 3D printing strategy for the construction of high-performance K metal anode.