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

Abstract

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.

A sodiophilic VN interlayer stabilizing a Na metal anode

“…5e). Obviously, these adsorption energies are negative, and significantly less than that of bare Na (−0.860 eV), 45 indicating that the Na ion is inclined to adsorb and deposit on the VN surface. Furthermore, the charge differential density illustrations of the Na ion on various sites of the VN surface further reveal the strong chemical interaction and fast charge transfer between them (Fig.…”

Sb2S3 Nanorod Hierarchies Enabling Homogeneous Sodium Deposition for Dendrite-Free Sodium-Metal Batteries

“…Additionally, it should be noted that the in situ generated Na 2 S species served as a buffer matrix is another key factor for realizing reversible and stable Na-metal batteries. 37 Indeed, it is noteworthy to mention that Sb alone is not sufficient enough to withstand the huge volume expansion (up to 390%), as evidenced by previous studies. 38,39 Moreover, even at high current densities and capacities (Figure 4b and c), the Na/Sb 2 S 3 electrodes still show low overpotentials of 27.2 and 28.5 mV with superior cycling stability over 700 cycles (namely, 1400 h, 3 mA cm −2 /3 mA h cm −2 ) and 500 cycles (namely, 1000 h, 5 mA cm −2 /5 mA h cm −2 ), respectively, whereas Na/Cu electrodes exhibit unstable voltage profiles with high overpotential (Figure 4b), even resulting in short circuit (Figure 4c).…”

Rational Design of an Artificial SEI: Alloy/Solid Electrolyte Hybrid Layer for a Highly Reversible Na and K Metal Anode

“…Moreover, the K 3 OCl/K 3 Bi@K symmetrical cell shows flat and stable plating/stripping profiles at 1.0 mA cm –2 (Figure S17), due to the uniform K deposition. Such an impressive performance shows absolute advantages in comparison with other reported potassium anodes (Figure d). ,,− In addition, in situ optical microscope tests were conducted to probe the potassium deposition behavior on the surface of bare K and K 3 OCl/K 3 Bi@K at a current density of 0.25 mA cm –2 (Figure S18). It is observed that K dendrites grow gradually on the bare K surface as time goes on.…”