Transforming a Primary Li-SOCl₂ Battery into a High-Power Rechargeable System via Molecular Catalysis

Li-SOCl₂ batteries possess ultrahigh energy densities and superior safety features at a wide range of operating temperatures. However, the Li-SOCl₂ battery system suffers from poor reversibility due to the sluggish kinetics of SOCl₂ reduction during discharging and the oxidation of the insulating discharge products during charging. To achieve a high-power rechargeable Li-SOCl₂ battery, herein we introduce the molecular catalyst I₂ into the electrolyte to tailor the charging and discharging reaction pathways. The as-assembled rechargeable cell exhibits superior power density, sustaining an ultrahigh current density of 100 mA cm^-2 during discharging and delivering a reversible capacity of 1 mAh cm^-2 for 200 cycles at a current density of 2 mA cm^-2 and 6 mAh cm^-2 for 50 cycles at a current density of 5 mA cm^-2. Our results reveal the molecular catalyst-mediated reaction mechanisms that fundamentally alter the rate-determining steps of discharging and charging in Li-SOCl₂ batteries and highlight the viability of transforming a primary high-energy battery into a high-power rechargeable system, which has great potential to meet the ever-increasing demand of energy-storage systems.