Influence of central atoms on the catalytic effect of transition metal phthalocyanines in Li-S battery cathodes

摘要

Transition metal phthalocyanines (MPc) with different central metal atoms of Co(II), Fe(II), Ni(II), Mn(II) and Cu (II) were loaded on carbon nanofibers to act as the cathode catalytic materials for Li-S batteries. The influence of central atoms on the catalytic activity was explored. Higher specific capacities and cycling stability were ach-ieved with CoPc and FePc, exhibiting higher catalytic activities for the oxidation and reduction processes respectively. The MPc molecules all present similar adsorption geometries with Li2S6 and adsorption energy was found to be unsuitable to explain the difference. The presence of unoccupied dz2 orbitals in Co and Fe might be the origin for the higher catalytic activities.