Smoothing the Sodium‐Metal Anode with a Self‐Regulating Alloy Interface for High‐Energy and Sustainable Sodium‐Metal Batteries

Abstract

Because of the large abundance of sodium (Na) as a source material and the easy fabrication of Na‐containing compounds, the sodium (Na) battery is a more environmentally friendly and sustainable technology than the lithium‐ion battery (LIB). Na‐metal batteries (SMBs) are considered promising to realize a high energy density to overtake the cost effectiveness of LIBs, which is critically important in large‐scale applications such as grid energy storage. However, the cycling stability of the Na‐metal anode faces significant challenges particularly under high cycling capacities, due to the complex failure models caused by the formation of Na dendrites. Here, a universal surface strategy, based on a self‐regulating alloy interface of the current collector, to inhibit the formation of Na dendrites is reported. High‐capacity (10 mAh cm−2) Na‐metal anodes can achieve stable cycling for over 1000 h with a low overpotential of 35 mV. When paired with a high‐capacity Na3V2(PO4)2F3 cathode (7 mAh cm−2), the SMB delivers an unprecedented energy density (calculated based on all the cell components) over 200 Wh kg−1 with flooded electrolyte, or over 230 Wh kg−1 with lean electrolyte. The dendrite‐free SMB also shows high cycling stability with a capacity retention per cycle over 99.9% and an ultrahigh energy efficiency of 95.8%.

Highly Potassiophilic Graphdiyne Skeletons Decorated with Cu Quantum Dots Enable Dendrite‐Free Potassium‐Metal Anodes

“…The collective merits of NC@GDY-Al in achieving high cyclic stability and high CE value not only surpass the other reported counterparts in PMB [29][30][31]33,34,49,50] (Figure 4f; Table S3, Supporting Information) but also compares favorably with those used in sodium metal batteries. [51][52][53] To evaluate the electrochemical stability of the designed NC@ GDY-Al current collector, symmetric cells with two identical electrodes via K electrodeposition were assembled and tested in KFSI-DME electrolyte at different current densities and capacities (Figure S19, Supporting Information). Figure 5a-c manifests the cycling stability of various electrodes under different cycling capacities from 0.5 through 2.0-4.0 mAh cm −2 , which corresponds to the DOD of 10%, 40%, and 80%, respectively.…”

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

“…The time-voltage curve of the Na 2 S/V/Na cell was stable, flat and smooth during the entire cycle process, with a low voltage polarization of 38 mV, indicating a stable artificial protective layer and rapid Na + transport. [28,39,40] In contrast, the bare Na and Na 2 S/Na symmetric cells exhibited short cycle lives of 24 and 292 h, respectively. A remarkably higher voltage polarization (100 mV) was observed for the bare Na symmetric cell at the beginning and end of each plating/stripping process, which indicates that the consumption of previously unused fresh Na below the traditional SEI layer.…”

Tailoring Ultrafast and High‐Capacity Sodium Storage via Binding‐Energy‐Driven Atomic Scissors

“…Sodium-ion batteries (SIBs) have drawn significant attention as a promising nextgeneration energy storage technology as a result of the large reserves and comparatively low cost of Na metal. [1][2][3][4][5][6] Given significant developments in open framework materials with kinetically favorable Na storage channels as SIB cathodes, [7][8][9][10][11][12][13] the concomitant development of advanced anodes possessing high capacities and rate capabilities is essential to enable the widespread implementation of SIBs. Among the various candidates, Ge, which has a bandgap of only 0.66 eV at 300 K, has become increasingly prominent as an anode material for sodium storage, owing to its remarkable electrical conductivity (≈100 times higher than that of Si), [14] high theoretical capacity (Na 3 Ge: 1108 mAh g −1 , NaGe: 369 mAh g −1 ), [15,16] rapid Na + transport properties, and superior mechanical strength.…”