Dispersion Guided Assembly of rGO/CNT Hybrids with Interlayer Bridging for Three-Dimensional Conductive Networks in...

Lithium iron phosphate (LiFePO₄, LFP) is severely limited by its intrinsically low electronic conductivity and sluggish lithium-ion diffusion kinetics, particularly under high-rate operating conditions. Therefore, introducing high-performance conductive additives to construct efficient electron transport networks has been considered an effective strategy for improving the rate capability and cycling stability of LFP cathodes. Among various conductive materials, reduced graphene oxide (rGO) and carbon nanotubes (CNT) have attracted extensive attention owing to their excellent electrical conductivity and unique structural advantages. However, the intrinsic tendency of rGO nanosheets to restack and CNT to entangle often hinders the construction of continuous and efficient conductive networks. Herein, an interfacial co-dispersion strategy is developed to regulate the assembly of graphene oxide (GO) and hydroxylated carbon nanotubes (CNT-OH), leading to the formation of an rGO/dCNT conductive architecture. Interfacial interactions associated with oxygen-containing functional groups facilitate the homogeneous co-dispersion of GO and CNT-OH in aqueous media, while partially hydroxylated CNTs are preintercalated between adjacent GO sheets to form an interlayer intercalation-bridging architecture. During the subsequent thermal reduction process, the prefabricated architecture efficiently inhibits the restacking of rGO nanosheets and simultaneously constructs interconnected lithium-ion transport pathways between adjacent layers, thereby forming a robust three-dimensional conductive network. When applied as a conductive additive for LiFePO₄ cathodes, the optimized rGO/dCNT composite (L-RO_2-1) delivers a discharge capacity of 159 mAh g^-1 at 0.2 C and maintains 104.3 mAh g^-1 after 300 cycles at 6 C, while exhibiting lower charge-transfer resistance and faster lithium-ion diffusion kinetics. This work provides an effective strategy for constructing stable carbon-based conductive networks for high-rate lithium-ion batteries.