Design of highly porous Fe 3 O 4 @reduced graphene oxide via a facile PMAA-induced assembly.

Advances in the synthesis and processing of graphene-based materials have presented the opportunity to design novel lithium-ion battery (LIB) anode materials that can meet the power requirements of next-generation power devices. In this work, a poly(methacrylic acid) (PMAA)-induced self-assembly process was used to design super-mesoporous Fe 3 O 4 and reduced-graphene-oxide (Fe 3 O 4 @RGO) anode materials. We demonstrate the relationship between the media pH and Fe 3 O 4 @RGO nanostructure, in terms of dispersion state of PMAA-stabilized Fe 3 O 4 @GO sheets at different surrounding pH values, and porosity of the resulted Fe 3 O 4 @RGO anode. The anode shows a high surface area of 338.8 m 2 g -1 with a large amount of 10-40 nm mesopores, which facilitates the kinetics of Li-ions and electrons, and improves electrode durability. As a result, Fe 3 O 4 @RGO delivers high specific-charge capacities of 740 mA h g -1 to 200 mA h g -1 at various current densities of 0.5 A g -1 to 10 A g -1 , and an excellent capacity-retention capability even after long-term charge-discharge cycles. The PMAA-induced assembly method addresses the issue of poor dispersion of Fe 3 O 4 -coated graphene materials-which is a major impediment in the synthesis process-and provides a facile synthetic pathway for depositing Fe 3 O 4 and other metal oxide nanoparticles on highly porous RGO.