In situ preparation of Fe3O4 in a carbon hybrid of graphene nanoscrolls and carbon nanotubes as high performance anode material for lithium-ion batteries.

A new conductive carbon hybrid combining both reduced graphene nanoscrolls and carbon nanotubes (rGNSs-CNTs) is prepared, and used to host Fe3O4 nanoparticles through an in situ synthesis method. As an anode material for LIBs, the obtained Fe3O4@rGNSs-CNTs shows good electrochemical performance. At a current density of 0.1 A g-1, the anode material shows a high reversible capacity of 1232.9 mAh g-1 after 100 cycles. Even at a current density of 1 A g-1, it still achieves a high reversible capacity of 812.3 mAh g-1 after 200 cycles. Comparing with bare Fe3O4 and Fe3O4/rGO composite anode materials without nanoscroll structure, Fe3O4@rGNSs-CNTs shows much better rate capability with a reversible capacity of 605.0 and 500.0 mAh g-1 at 3 and 5 A g-1, respectively. The excellent electrochemical performance of the Fe3O4@rGNSs-CNTs anode material can be ascribed to the hybrid structure of rGNSs-CNTs, and their strong interaction with Fe3O4 nanoparticles, which on one hand provides more pathways for lithium ions and electrons, on the other hand effectively relieves the volume change of Fe3O4 during the charge-discharge process.

Oriented Arrangement: The Origin of Versatility for Porous Graphene Materials.

Macroscopic porous graphene materials composed of graphene sheets have demonstrated their advantageous aspects in diverse application areas. It is essential to maximize their excellent performances by rationally controlling the sheet arrangement and pore structure. Bulk porous graphene materials with oriented pore structure and arrangement of graphene sheets are prepared by marrying electrolyte-assisted self-assembly and shear-force-induced alignment of graphene oxide sheets, and the super elasticity and anisotropic mechanical, electrical, and thermal properties induced by this unique structure are systematically investigated. Its application in pressure sensing exhibits ultrahigh sensitivity of 313.23 kPa-1 for detecting ultralow pressure variation below 0.5 kPa, and it shows high retention rate for continuously intercepting dye molecules with a high flux of ≈18.7 L m-2 h-1 bar-1 and a dynamic removal rate of 510 mg m-2 h-1 .

Electrocatalytic activity of silver decorated ceria microspheres for the oxygen reduction reaction and their application in aluminium-air batteries.

Nanosheet-constructing porous CeO2 microspheres with silver nanoparticles anchored on the surface were developed as a highly efficient oxygen reduction reaction (ORR) catalyst. The aluminum-air batteries applying Ag-CeO2 as the ORR catalyst exhibit a high output power density and low degradation rate of 345 mW cm-2 and 2.6% per 100 h, respectively.