One-Step In Situ Formation of N-doped Carbon Nanosheet 3D Porous Networks/TiO_2 Hybrids with Ultrafast Sodium Storage

摘要

In spite of the satisfactory advancement in preparing TiO2-based hybrid structures, most methods rely on additional template-based multistep reactions for engineering the given structure. Herein, a unique self-template and in situ recrystallization strategy is explored to synthesize uniform flowerlike multicompositional structures of nitrogen-doped porous carbon nanosheet networks immobilizing TiO2 nanoparticles (TiO2 boolean AND NPCSs) via a self-prepared single precursor and subsequent thermal treatment. Depending on the unique coordination ability of 2,4-dihydroxybenzoic acid with metal ions under alkaline conditions to form a flowerlike network, a self-produced single precursor can be achieved. Careful investigations of the self-prepared precursor reveal a high practicability of the present synthetic scheme. Because of the novel structural and compositional features, these TiO2 boolean AND NCSN flowers indicate superior sodium storage properties when evaluated as anodes for sodium-ion batteries. Impressively, the TiO2 boolean AND NCSN flowers deliver high reversible capacities of 152 mAh g(-1) at 2C for 3000 cycles and 114 mAh g(-1) at 10C for 10000 cycles, as well as an ultrahigh rate capability up to 50C with a capacity of 101 mAh g(-1). The facile method could stimulate further capability in precise construction of complex architectures with complicated compositions for different device applications.