Tailoring fluorine-substituted cobalt phthalocyanine/activated carbon nanocomposites for stable and long-life Li/SOCl2 batteries

CoPcF4 nanorods fixed on activated carbon substrates (CoPcF4/AC) were created using an in situ solid approach for catalysts to improve the response of thionyl chloride (SOCl2). Density functional theory calculations showed that the benzene rings around the CoPcF4 molecule exhibited a positive electrostatic potential, providing multiple active sites for the SOCl2 reduction reaction. Moreover, the combination investigations from SEM and focused ion beam-SEM indicated that a loose and porous LiCl film appeared on the surface of the carbon cathode containing CoPcF4/AC, facilitating the permeation of newly formed LiCl. The inside morphology of the carbon cathodes discharged displayed a substantial number of nanopores around 50 nm, which could be attributed to the CoPcF4/AC nanocomposites inducing the nucleation of nanosized LiCl on the surface and inside to keep the cathode with a porous structure, benefitting from the SOCl2 reduction reaction. The Li/SOCl2 battery catalyzed by the CoPcF4/AC exhibited a stable voltage platform around 2.8 V, lasted 98.2 % during the entire discharge process, and had a relative energy improvement of 181.03 % and 147.89 % compared with those containing CoPc and CoPcF4, respectively.