Free-Standing Na_(2/3)Fe_(1/2)Mn_(1/2)O2@Graphene Film for a Sodium-Ion Battery Cathode

摘要

The development of high-performance cathodes for sodium-ion batteries remains a great challenge, while low-cost, high-capacity Na_(2/3)Fe_(1/2)Mn_(1/2)O2 is an attractive electrode material candidate comprised of earth-abundant elements. In this work, we designed and fabricated a free-standing, binder-free Na_(2/3)Fe_(1/2)Mn_(1/2)O2@graphene composite via a filtration process. The porous composite led to excellent electrochemical performance due to the facile transport for electrons and ions that was characterized by electrochemical impedance spectroscopy at different temperatures. The electrode delivered a reversible capacity of 156 mAh/g with high Coulombic efficiency. The importance of a fluorinated electrolyte additive with respect to the performance of this high-voltage cathode in Na-ion batteries was also investigated.