Liquid Metal‐Organic Frameworks In‐Situ Derived Interlayer for High‐Performance Solid‐State Na‐Metal Batteries

Abstract

Despite recent progress in solid‐state Na‐metal batteries (SSNBs) based on inorganic solid‐state electrolytes (SSEs), Na dendrite propagation due to interfacial Na+ transport inhomogeneity and heterogeneous Na stripping/plating processes, greatly hinders the improvement of the cycling stability of SSNBs. Herein, the characteristics and propagation mechanism of Na dendrite growth in SSNBs are comprehensively analyzed. Confronted with Na dendrites, a novel strategy is developed to in‐situ modify a SSE surface with a liquid metal–organic frameworks (MOFs) precursor. The interlayer is directly obtained from high‐temperature monophasic liquid MOFs, not interfering with intermediate recrystallization, thus endowing superior uniformity. It can improve interfacial compatibility with the Na‐anode and homogenize e−/Na+ transport kinetics, leading to spatially even Na nucleation and thus a transition of Na deposition behavior from dendrites to a lateral flat‐shape growth tendency. Furthermore, the obtained sodiophilicity interlayer shows isotropous and stable characteristics to alleviate stress/strain and maintain excellent interfacial stability during cycling. Therefore, the assembled Na symmetric batteries demonstrate a top‐level time‐terminated critical current density of 1.0 mA cm−2, and the integrated full cells show a stable cycling performance for 500 cycles at 1 C. The presented liquid MOFs in‐situ derived strategy to suppress dendrites propagation is expected to be promising for other solid‐state batteries.

Pressure‐ and Temperature‐Dependent Interface Kinetics in Na3Zr2Si2PO12‐Based All‐Solid‐State Na Metal Battery

“…This is in agreement with other observations for Naand Li-based ceramic SSEs. [33,34] A slice of the short-circuited SSE was scanned to determine the elemental distribution in the SSE (Figure 5b). EDS spectra show the presence of NASICON core elements (Na, Si, P, Zr, and O).…”

Atomically bonding Na anodes with metallized ceramic electrolytes by ultrasound welding for high‐energy/power solid‐state sodium metal batteries

“…The cross‐section SEM image of the SP Na/NZSP interface (Figure 2B) manifests the huge gap and poor contact, which would cause huge interface resistance, failure of Na + transport, and uneven Na electroplating/stripping 26 . Nevertheless, for the UW Na/NZSP interface, although an intimate and dense interface layer can be observed (Figure 2C), the low ionic conductivity of the interfacial Na 2 SiO 3 interlayer would induce inhomogeneous Na + transport 15,27 . Moreover, due to the absence of the protective layer between Na and NZSP, the highly spontaneous reactivity gradually decreases the proportion of the highly ion‐conductive NZSP solid‐state electrolyte.…”

“…Although the sodium silicates are considered Na + conductors and used as addition agents in NZSP ceramics during sintering to effectively increase the ionic conductivity resulting from the decreased grain boundary resistance, 12,13 the intrinsic ionic conductivity of sodium silicates (10 −6 S cm −1 ) is lower than that of the NZSP (10 −4 S cm −1 ) 14 . Besides, the uncontrolled reaction between Na and NZSP accompanied by the continuous formation of sodium silicates seriously increases interfacial resistance and decreases critical current density (CCD), resulting in uneven Na dendrite growth and battery failure 8,15 …”

“…Nevertheless, high temperature and pressure would accelerate the side reaction of Na and NZSP and go so far as to have the possibility of penetrating the Na metal throughout the NZSP pellet. The interlayer introduction (e.g., MOFs, 15 AlF 3 , 18 TiO 2 , 19 and Sn/SnO x 20 ), serving as a mechanical buffer matrix, was considered to be an effective way to refine interfacial contact by suppressing dendrite growth and reducing the interfacial resistance. Recently, a room‐temperature ultrasound welding method was reported by our group to construct a tightly bonding interface between Na and NZSP electrolytes 11 .…”

NaSICON: A promising solid electrolyte for solid‐state sodium batteries

“…The assembled Na symmetric batteries exhibited a high CCD of 1.0 mA cm −2 . [ 117 ] Similar strategies include the formation of the polymer layer, [ 113,118 ] metal oxide, [ 59,119 ] AlF 3 , [ 120 ] and other carbonaceous materials [ 121 ] as interlayers between NaSICON electrolyte and Na metal were found to improve the wetting and compatibility of NaSICON electrolyte with metallic Na.…”