Ultra-Long and Rapid Operating Sodium Metal Batteries Enabled By Multifunctional Polarizable Interface Stabilizer

Sodium metal batteries (SMBs) have been considered as one of the most favorable and economic candidates for next generation batteries to overcome low enenrgy density limitation of sodium ion batteries (SIBs) due to high theoretical specific capacity (1166 mAh g-1), low electrochemical redox potential (-2.71 V vs. SHE). However, ‘moss-like’ dendrite growth that occurs during continuous charging and discharging processes not only threatens the safety of batteries, but also poses several problems to be solved, such as electrolyte consumption, hugh volume expansion, dead Na formation, and low coulombic efficiency. The dendrite problem in the SMBs is similr to that of lithium-metal batteries (LMBs), yet the degree of the issue is further severe than LMBs. Surface stabilization of sodium metal anode should be achieved to realize SMB technologies. The introduction of functional electrolyte additives is an effective and economical way to overcome these problems and improve the cyclability of SMBs. Based on the similarity between electroplating and sodium deposition reaction, utilization of surface leveler additive in the electrolyte could allow a substantial impact to stabilize sodium metal surface during repeated deposition and stripping process. In this presentation, we confirmed the surface flattening effect of molecular dipole electrolyte additives at the anode through the Na-Na symmetric cell test. Sodium metal deposition and stripping behavior has been successfully controlled by introducing surface leveler additives for realization of SMBs. Even under rapid charging and discharging situations, additive containing Na-Na symmetric cells showed stable performance for over 2000 hours, which is 5 times longer than the pristine cell without the additive. We confirmed that controlling intrinsic properties of surface leveler additive can effectively further improve cycle performance of SMBs. [1] S.-Y. Jun, K. Shin, C. Y. Son, J. Park, H.-S. Kim, J.-Y. Hwang, W.-H. Ryu, Advanced Energy Materials, 2024, 2304504 [2] S.-Y. Jun, K. Shin, Y. Lim, S. Kim, H. Kim, C. Y. Son, W.-H. Ryu, Small Structures, 2024, 5, 2300578 [3] S.-Y. Jun, K. Shin, J.-S. Lee, S. Kim, J. Chun, W.-H. Ryu, Advanced Science, 2023, 10, 2301426 [4] J.-S. Lee, K. Shin, S.-Y. Jun, S. Kim, W.-H. Ryu, Chemical Engineering Journal, 2023, 458, 141383 Figure 1