Artificial Heterogeneous Interphase Layer with Boosted Ion Affinity and Diffusion for Na/K-Metal Batteries

Metallic Na (K) are considered a promising anode materials for Na-metal and K-metal batteries because of their high theoretical capacity, low electrode potential, and abundant resources. However, the uncontrolled growth of Na (K) dendrites severely damages the stability of the electrode/electrolyte interface, resulting in battery failure. Herein, a heterogeneous interface layer consisting of metal vanadium nanoparticles and sodium sulfide (potassium sulfide) is introduced on the surface of a Na (K) foil (i.e., Na2S/V/Na or K2S/V/K). Experimental studies and theoretical calculations indicate that a heterogeneous Na2S/V (K2S/V) protective layer can effectively improve Na (K)-ion adsorption and diffusion kinetics, inhibiting the growth of Na (K) dendrites during Na (K) plating/stripping. Based on the novel design of the heterogeneous layer, the symmetric Na2S/V/Na cell displays a long lifespan of over 1000 h in a carbonate-based electrolyte, and the K2S/V/K electrode can operate for over 1300 h at 0.5 mA cm(-2) with a capacity of 0.5 mAh cm(-2). Moreover, the Na full cell (Na3V2(PO4)(3)||Na2S/V/Na) exhibits a high energy density of 375 Wh kg(-1) and a high power density of 23.5 kW kg(-1). The achievements support the development of heterogeneous protective layers for other high-energy-density metal batteries.

Automated summary

Metallic Na (K) is a promising anode material for Na-metal and K-metal batteries, but the growth of Na (K) dendrites affects their stability. This study introduces a heterogeneous interface layer to improve the performance of the batteries, resulting in enhanced lifespan, capacity, energy density, and power density.