Packing FeF₃·0.33H₂O into porous graphene/carbon nanotube network as high volumetric performance cathode for lithium ion battery

Preparation of nanostructures and combining with carbon materials can solve the problem of poor conductivity of FeF₃·0.33H₂O cathode material. But the fatal drawback is that this will greatly reduce the volumetric energy density. To solve this problem, a multi-stage micro-nano structured porous graphene/carbon nanotube/FeF₃·0.33H₂O possess high volumetric energy density is constructed in this work. The FeF₃·0.33H₂O nanoparticles generate by the solvothermal process are not only embedded on the surface of carbon nanotubes and graphene, but also partially agglomerated into micron-sized spheres embed in the graphene layers which can greatly increase the areal mass loading. And the addition of carbon nanotubes not only hinders the self-stacking of graphene layers, but also acts as highly conductive wires to enhance the conductivity between the graphene layers. Good rate capability with high mass loading can be achieved due to the effect of micro-nano-structured FeF₃·0.33H₂O particles packing into the three-dimensional conductive network constructed by carbon nanotubes and graphene. The composite exhibits excellent rate capability with discharge capacities of 148 mAh g⁻¹at 1C (1C = 200 mA g⁻¹) rate under high mass loading of 5 mg cm⁻².