Rechargeable Sodium Solid‐State Battery Enabled by In Situ Formed Na–K Interphase

Abstract

Solid‐state metal batteries have displayed great advantages in the domain of electrochemical energy storage owing to their remarkably improved energy density and safety. However, the practical application of solid‐state batteries (SSBs) is still greatly impeded by unfavorable interface stability and terrible low temperature performance. In this work, a local targeting anchor strategy is developed to realize an impressively long cycling life for a NASICON‐based solid‐state sodium metal battery at 0 °C. With the electrochemical migration of K+ from the cathode side to the anode side, a spontaneous generated liquid Na–K interphase can stabilize the ceramic electrolyte/metallic Na anode interface, and address the issues of sluggish kinetics at the interface together with metal dendrite deposition. In addition, the capability of K+ conduction in NASICON is also theoretically and experimentally validated. Of particular note, a K2MnFe(CN)6 cathode paired with a Na3Zr2Si2PO12 ceramic electrolyte and metallic Na anode, enable the long‐term cycling and excellent rate capability of all‐solid‐state sodium batteries at 0 °C. Without the purposely designed matrix host for a liquid Na–K interphase, this work opens up a new route for the design of high energy density SSBs.

Rechargeable Solid‐State Na‐Metal Battery Operating at −20 °C

“…Moreover, the performance of the solid-state NVAP-PCE|0.15Ca-NZSP|Na battery surpasses those of most NZSPbased solid-state batteries documented in previous literature (Table S1, Supporting Information). [20,24,27,[29][30][31][32][45][46][47]50,62] The robust wide-temperature performance of the NVAP-PCE|0.15Ca-NZSP|Na battery can be credited to the steady Na-metal plating/stripping behavior at the anodic interface and the excellent low-temperature properties of the NVAP cathode material. [61]…”

“…A comprehensive examination and investigation of the temperature-dependent electrochemical behavior of SS-NMBs using inorganic SEs has been rarely conducted over a wide temperature range encompassing all-season conditions, particularly temperatures below 0 °C. [20,32] In this study, we present the first demonstration of a rechargeable SSNMB operating over a wide temperature range from −20 to 45 °C. We achieved this by incorporating a calcium ion (Ca 2+ )-doped Na 3 Zr 2 Si 2 PO 12 (Ca-NZSP) SE, which effectively stabilizes the Na-metal anode and enables smooth Na-metal plating/stripping cycles even at low temperatures.…”

“…[18,19] Considering practical application scenarios, there is a pressing need to explore effective strategies that enhance interface kinetics and reduce the operating temperature threshold of SSNMBs. [20,21] In recent years, significant efforts have been directed toward SSNMBs utilizing a Natrium super ionic conductor (NASICON) NASICON-type Na 3 Zr 2 Si 2 PO 12 (NZSP) SE. [22] Various interfaceinterphase engineering methods have been proposed to address the challenges of Na + -ion transport, suppression of Na-metal dendrite formation, and long-term cycling stability of SSNMBs under ambient temperatures.…”

“…2 Si 2 PO 12 SE by incorporating Cu 2+ /Cu + redox, resulting in a favorable interphase layer of Cu 3 PO 4 , thereby facilitating a NaCrO 2 -based SSNMB with long-term cycling performance at 25 °C. Ni et al [20] employed electrochemical migration of K + from the cathode side to the anode side to generate an in situ Na-K alloy interphase, thereby promoting kinetics at the Na/NZSP interface and enabling the operation of a K 2 MnFe(CN) 6 ||Na SSNMB at 0 °C. Additionally, methods such as constructing monolithic structures, [28] designing grain boundaries, [29][30][31] doping the SEs with metal ions, [32] and modifying the Na-metal anode [33] have been reported to reduce interfacial resistance and facilitate dendrite-free Na-metal plating/stripping behavior.…”

Recent progress and strategic perspectives of inorganic solid electrolytes: fundamentals, modifications, and applications in sodium metal batteries

“…, the in situ formation of the fluorine/chorine-rich interface layer 587,588,687,788,789 and the Na-K alloy interface layer. 790…”