Advantages and Sustainability of Sodium-Ion Batteries Integrated with Fire Suppressants: A Pathway to Safer and Greener Energy Storage

Sodium-ion batteries (SIBs) are gaining attention as safer and cost-effective alternatives to lithium-ion batteries, but challenges remain in improving their safety, performance, and sustainability. This study explores advancements in electrolyte additives, polymer electrolytes, separators, and poly-ionic membranes to enhance SIB efficiency and safety. Sodium bis(oxalato)borate (NaBOB) was identified as a non-flammable and fluoride-free alternative to toxic NaPF6 in trimethyl phosphate (TMP), achieving thermal stability up to 300°C, high ionic conductivity (5 × 10⁻³ S cm⁻¹), and 97% coulombic efficiency. Incorporating vinylene carbonate (VC) mitigates discharge capacity degradation over cycling. Flexible polymer electrolytes, such as PPEGMA-gel systems, demonstrate resilience to mechanical shocks with a capacity retention of 91% after 400 cycles and a wide voltage range of 4.8 V, though high-temperature performance requires further investigation. Organic electrolyte blends with 10 vol% fluoroethylene carbonates (FEC) improve electrode stability, enabling energy densities of up to 1246 Wh kg⁻¹ after 300 cycles. Advanced separators, such as ZrO₂/PVDF-HFP-coated polyolefins, exhibit enhanced Na⁺ conductivity (7 × 10⁻⁴ S cm⁻¹) but require ceramic modifications for higher thermal resilience, achieving stability up to 500°C with barium titanate integration. Hierarchical poly-ionic liquid-based solid electrolytes (HPILSE) outperform conventional membranes in flexibility, thermal stability (up to 300°C), and resistance to mechanical stress. Future studies are essential to optimize ionic conductivity through additive research. This comprehensive exploration of materials and configurations offers promising directions for the development of safe, efficient, and durable sodium-ion batteries.