A Bidirectional Ion Kinetic Regulator Suppressing Lithium Dendrites in Advanced Lithium-Sulfur Batteries

Liquid organic electrolytes (LOEs) are of crucial significance in secondary battery deposition processes. Based on Sand's time formula, this study proposes a novel bidirectional ion kinetic regulator concept. Verified in lithium-sulfur batteries (LSBs), it is demonstrated that regulating the migration of anions and cations simultaneously can effectively promote the realization of dendrite-free batteries. This bidirectional ion kinetic regulator forms octahedral complexes with TFSI⁻, decreasing TFSI⁻ migration, enhancing Li⁺ desolvation and diffusion, and thus extending the dendrite formation time by over 25 times. Moreover, the attraction of the regulator towards solvent molecules and its improvement on the sulfur reduction kinetics effectively suppress the shuttle effect. Subsequently, the assembled Li||Li (1 mA cm⁻² for 2000 h), Li-Cu (99.4% of CE), and Li-S (1000 cycles at 4 C) cells deliver extremely excellent cycling stability. An Ah-level Li-S pouch cell also exhibits negligible capacity decay (50 cycles without capacity decay). This confirms the importance of regulating both anions and cations for high-safety LSBs.