Graphene based magnetite carbon nanofiber composites as anodes for high-performance Li-ion batteries

For energy storage applications, highly flexible free-standing electrodes are ideal for the fabrication of electrochemical cells.

Magnetically active lithium-ion batteries towards battery performance improvement

Lithium-ion batteries (LIBs) are currently the fastest growing segment of the global battery market, and the preferred electrochemical energy storage system for portable applications. Magnetism is one of the forces that can be applied improve performance, since the application of magnetic fields influences electrochemical reactions through variation of electrolyte properties, mass transportation, electrode kinetics, and deposits morphology. This review provides a description of the magnetic forces present in electrochemical reactions and focuses on how those forces may be taken advantage of to influence the LIBs components (electrolyte, electrodes, and active materials), improving battery performance. The different ways that magnetic forces can interact with LIBs components are discussed, as well as their influence on the electrochemical behavior. The suitable control of these forces and interactions can lead to higher performance LIBs structures and to the development of innovative concepts.

Design of highly porous Fe3O4@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 Fe3O4 and reduced-graphene-oxide (Fe3O4@RGO) anode materials. We demonstrate the relationship between the media pH and Fe3O4@RGO nanostructure, in terms of dispersion state of PMAA-stabilized Fe3O4@GO sheets at different surrounding pH values, and porosity of the resulted Fe3O4@RGO anode. The anode shows a high surface area of 338.8 m2 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, Fe3O4@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 Fe3O4-coated graphene materials-which is a major impediment in the synthesis process-and provides a facile synthetic pathway for depositing Fe3O4 and other metal oxide nanoparticles on highly porous RGO.