A room-temperature sodium rechargeable battery using an SO2-based nonflammable inorganic liquid catholyte

Abstract

Sodium rechargeable batteries can be excellent alternatives to replace lithium rechargeable ones because of the high abundance and low cost of sodium; however, there is a need to further improve the battery performance, cost-effectiveness, and safety for practical use. Here we demonstrate a new type of room-temperature and high-energy density sodium rechargeable battery using an SO2-based inorganic molten complex catholyte, which showed a discharge capacity of 153 mAh g−1 based on the mass of catholyte and carbon electrode with an operating voltage of 3 V, good rate capability and excellent cycle performance over 300 cycles. In particular, non-flammability and intrinsic self-regeneration mechanism of the inorganic liquid electrolyte presented here can accelerate the realization of commercialized Na rechargeable battery system with outstanding reliability. Given that high performance and unique properties of Na–SO2 rechargeable battery, it can be another promising candidate for next generation energy storage system.

A Sugar-Derived Room-Temperature Sodium Sulfur Battery with Long Term Cycling Stability

“…Confinement efforts for lithium sulfur batteries were abandoned because the necessary micropore size (<1 nm) limits sulfur mass loadings to under 50 wt %, − and higher loadings (>70%) are necessary to reach appropriately high gravimetric energy density that dictates their use as advanced Li-ion carriers . However, early sodium sulfur batteries without confinement (elemental S 8 cathodes) yield poor sulfur conversion ,,− unless additional device elements including interlayers or dense solid electrolytes adding excessive mass, volume, and cost are employed. ,,− Whereas microporous confinement lowers the overall energy density because higher voltage conversion of soluble products is excluded, effective implementation of the strategy can still deliver 2 times the energy density of Li-ion and significant reliability is gained . Initial confinement works have shown significantly improved sulfur conversion and cyclability − (Table S1) but all suffer from low Coulombic efficiency due to an unstable anode-electrolyte interface.…”

Developments and Perspectives on Emerging High-Energy-Density Sodium-Metal Batteries

“…Referring to the achievements on Li-SO 2 , [47][48][49] rechargeable Na-SO 2 batteries were first proposed by Kim's group and can be one of the promising candidates for next-generation energy storage systems as well. 50 The research on Na-SO 2 batteries is at the primary stage, focusing on obtaining reversible performance.…”

Lithium-Ion Intercalation into Graphite in SO2-Based Inorganic Electrolyte toward High-Rate-Capable and Safe Lithium-Ion Batteries

“…The Li–SO 2 rechargeable battery system was introduced about 30 years ago, and the employed SO 2 -based inorganic liquid electrolyte (LiAlCl 4 · x SO 2 ) showed nonflammability, high ionic conductivity (about 80 mS cm –1 at room temperature (Figure S1)), and a wide range of working temperatures. − Considering these outstanding properties, our group has revisited the rechargeable SO 2 -based inorganic liquid electrolyte battery system using various materials, alkali metal changed to Na, − and various electrolyte configurations for high energy density combined with high safety than that of the currently used LIB systems. As explained above, we expect that the nonflammability, high ionic conductivity (about 80 mS cm –1 at room temperature), and wide range of working temperatures of SO 2 -based inorganic liquid electrolyte will improve the LIB performance and safety.…”