Dynamic polarization control unlocks long-life, high-efficiency Lithium-Sulfur batteries

Abstract

Lithium‑sulfur (LiS) batteries offer exceptional theoretical capacity and energy density but are hindered in practice by sluggish reaction kinetics and severe polarization effects. Here, we introduce a pioneering Polarization-Controlled Charging Protocol (PPC) that dynamically adjusts the charging current in real time by maintaining a constant polarization threshold. This strategy accelerates charging in kinetically favorable regimes while suppressing current in polarization-prone regions, thereby preserving electrode structure and extending cycle life. The PPC yields a linear voltage-time charging profile, enabling direct state-of-charge (SOC) estimation and accurate charging time prediction. Average long-term cycling demonstrates that PPC can double battery lifespan. Compared to constant-current charging (CC), PPC achieves over 800 stable cycles at selected C-rates, while CC leads to faster capacity fading. The found average Li diffusion coefficient in PPC is seven times higher than that of the CC conditions, supporting hasted reaction kinetics. Overall, PPC reduces degradation by ∼69 % under equivalent average kinetics conditions, and offers a non-chemical, kinetics-responsive strategy to enhance durability, efficiency, and control in LiS batteries, with strong relevance for high-demand applications such as electric mobility.