Smart Hybridization of TiO2 Nanorods and Fe3O4 Nanoparticles with Pristine Graphene Nanosheets: Hierarchically Nanoengineered Ternary Heterostructures for High-Rate Lithium Storage

Today, the ever-increasing demand for large-size power tools has provoked worldwide competition in developing lithium-ion batteries having higher energy and power densities. In this context, advanced anode materials are being extensively pursued, among which TiO2 is particularly promising owing to its high safety, excellent cost and environmental performances, and high cycle stability. However, TiO2 is faced with two detrimental deficiencies, that is, extremely low theoretical capacity and conductivity. Herein, a smart hybridization strategy is proposed for the hierarchical co-assembly of TiO2 nanorods and Fe3O4 nanoparticles on pristine graphene nanosheets, aiming to simultaneously address the capacity and conductivity deficiencies of TiO2 by coupling it with high-capacity (Fe3O4) and high-conductivity (pristine graphene) components. The resulting novel, multifunctional ternary heterostructures effectively integrate the intriguing functionalities of the three building blocks: TiO2 as the major active material can adequately retain such merits as high safety and cycle stability, Fe3O4 as the auxiliary active material can contribute extraordinarily high capacities, and pristine graphene as the conductive dopant can guarantee sufficient percolation pathways. Benefiting from a remarkable synergy, the ternary heterostructures deliver superior reversible capacities and rate capabilities, thus casting new light on developing next-generation, high-performance anode materials.