Pulsed electrophoretic deposition of nanographitic flake-nanostructured Co3O4 layers for efficient lithium-ion-battery anode

Abstract

In spite of the high capacity of Co3O4 nanomaterial to employ in lithium-ion battery anodes, the reduced conductivity and significant volume change of Co3O4 during long cycling of insertion and extraction of Li ions remain a challenge. Utilization of composite materials making use of graphene-based materials together with Co3O4 nanostructures can offer a suitable strategy to address these challenges. Here, a composite material consisting of nanographitic flake and CO3O4 nanoparticles is synthesized by solvothermal reactions. After successive oxidation treatments, two types of electrophoretic deposition processes, namely, direct current and square wave pulse current are used to fabricate binder-free anodes for lithium-ion batteries. Compared to the direct current electrophoretic deposition technique, the pulsed electrophoretic deposition technique with a square wave is found to enhance the efficiency of the fabricated anode. The pulsed electrophoretic deposition technique enables the formation of the anode from smaller agglomerated Co3O4 nanoparticles compared to the anode obtained with the direct current electrophoretic deposition. The selective deposition of less agglomerated Co3O4 nanoparticles results in an excellent rate capability and durability of the anode fabricated by the pulsed electrophoretic deposition (a charge capacity of 780 mAh/g after 50 cycles at 1 A/g with total retention of 89%).