Synergetic Catalysis of Cobalt Tetrapyridylporphyrin and Copper Phthalocyanine to Promote the Discharge Behaviors in Li/SOCl2 Batteries

The sluggish reduction kinetics of thionyl chloride and the cathode passivation induced by the densification deposition of discharge product LiCl are critical challenges that severely hinder the commercialization of lithium/thionyl chloride (Li/SOCl2) batteries. In this work, a dual-catalyst cobalt tetrapyridine porphyrin (CoTAP) and copper phthalocyanine (CuPc) supported on activated carbon (AC) were proposed to synergically regulate SOCl2 reduction and product deposition. When the CoTAP/CuPc/AC catalyst was synthesized and applied as the cathode of Li/SOCl2 batteries, UV-Vis spectroscopy, crystal field coordination structure analysis, DFT calculations and XPS measurements collectively demonstrated that CoTAP catalyzes SOCl2 reduction through coordination at Co sites and strongly adsorbs Cl−, while CuPc features a weakly coordinated Cu center that facilitates the migration of LiCl products from the cathode surface. This collaborative effect in CoTAP/CuPc/AC cathodes effectively accelerates the reduction kinetics of SOCl2 and promotes the ordered deposition of product LiCl, thereby guaranteeing the continuous and progressive discharge process in Li/SOCl2 batteries. As a result, the CoTAP/CuPc/AC-catalyzed batteries exhibited excellent electrochemical performance with a stable discharge voltage of 3.16 V and high discharge capacity of 15.08 mAh, superior to the counterpart batteries without catalysts. This work provides a design idea for the development of advanced Li/SOCl2 batteries.