Enhancing Interfacial Strength and Wettability for Wide‐Temperature Sodium Metal Batteries

Abstract Development of high‐performance sodium metal batteries (SMBs) with a wide operating temperature range (from −40 to 55 °C) is highly challenging. Herein, an artificial hybrid interlayer composed of sodium phosphide (Na3P) and metal vanadium (V) is constructed for wide‐temperature‐range SMBs via vanadium phosphide pretreatment. As evidenced by simulation, the VP‐Na interlayer can regulate redistribution of Na+ flux, which is beneficial for homogeneous Na deposition. Moreover, the experimental results confirm that the artificial hybrid interlayer possesses a high Young's modulus and a compact structure, which can effectively suppress Na dendrite growth and alleviate the parasitic reaction even at 55 °C. In addition, the VP‐Na interlayer exhibits the capability to knock down the kinetic barriers for fast Na+ transportation, realizing a 30‐fold decrease in impedance at −40 °C. Symmetrical VP‐Na cells present a prolonged lifespan reaching 1200, 500, and 500 h at room temperature, 55 °C and −40 °C, respectively. In Na3V2(PO4)3||VP‐Na full cells, a high reversible capacity of 88, 89.8, and 50.3 mAh g−1 can be sustained after 1600, 1000, and 600 cycles at room temperature, 55 °C and −40 °C, respectively. The pretreatment formed artificial hybrid interlayer proves to be an effective strategy to achieve wide‐temperature‐range SMBs.