A Wide Temperature Range Sodium Solid-state Battery Resistant to Extreme Environments for Deep Space Exploration

To address the urgent demand for energy storage systems with wide-temperature-range adaptability and high safety under extreme environments such as deep space exploration and polar observation, a novel organic–inorganic composite sodium solid electrolyte has been developed for constructing high-performance sodium solid-state batteries. The electrolyte was synthesized by combining methylammonium lead chloride (MAPbCl₃) with a perovskite structure as the inorganic ion conductor, Sodium Alginate (SA) as the flexible polymer backbone, and Ethoxylated Trimethylolpropane Triacrylate (ETPTA) as a multifunctional crosslinker. Through in-situ Ultraviolet (UV)-initiated polymerization, a dense and robust composite polymer network was formed, ensuring homogeneous dispersion of inorganic fillers and intimate interfacial contact. Electrochemical characterization revealed that the as-prepared composite electrolyte exhibited a high ionic conductivity of 5.65×10^–4 S·cm^–1 and a sodium-ion transference number of 0.65 at room temperature, which are significantly higher than those of conventional ex-situ mixed systems. The assembled NVP|MSE-s|Na all-solid-state battery delivered excellent cycling stability, retaining 71.5% of its initial capacity after 500 cycles at 50 mA·g^–1 and maintaining good electrochemical performance across a wide temperature range from –40 ℃ to 80 ℃. Even at subzero temperatures, the cell showed stable charge/discharge behavior and suppressed dendritic growth. Further analyses confirmed that the in-situ formed composite structure effectively enhanced interfacial compatibility, thermal stability, and mechanical integrity, leading to reduced interfacial impedance and improved long-term cycling durability. These synergistic effects enabled the electrolyte to withstand harsh thermal and mechanical conditions while maintaining fast Na⁺ transport. This work demonstrates that integrating perovskite-type inorganic conductors within a UV-cured polymer matrix via in-situ polymerization is an effective strategy for constructing wide-temperature solid electrolytes. The proposed composite electrolyte system holds great promise as a safe and reliable energy storage solution for sodium solid-state batteries in extreme environments, particularly for applications such as deep space exploration, polar expeditions, and aerospace electronics.