A universal strategy for the in situ synthesis of TiO2(B) nanosheets on pristine carbon nanomaterials for high-rate lithium storage

Abstract

TiO₂(B) nanosheets exhibit high theoretical capacity and excellent cyclability for lithium storage, but suffer from disappointing rate capabilities because of their inherently low electronic and ionic conductivities as well as strong tendency to aggregate. Here we propose a universal strategy for the in situ synthesis of TiO₂(B) nanosheets on pristine carbon nanomaterials, e.g., pristine graphene nanosheets (PGNSs) and pristine carbon nanotubes (PCNTs), with the help of a multifunctional linker (SDBS). The resulting TiO₂(B)@PGNS and TiO₂(B)@PCNT nanohybrids energetically integrate the appealing merits of the two building blocks. Pristine carbon nanomaterials play three vital roles: first, they serve as high-efficiency conductive dopants to provide sufficient pathways for electrons and Li⁺ ions. Second, they act as flexible matrices to immobilize TiO₂(B) nanosheets and thus prevent them from aggregation. Last but not least, they can make a substantial capacity contribution. TiO₂(B) nanosheets, on the other hand, function not only as a major active material to achieve high structural stability and excellent cyclability, but also as spacers to isolate the pristine carbon nanomaterials from agglomeration. Benefiting from a remarkable synergistic effect, these two nanohybrids exhibit superior electrochemical lithium storage performance, particularly high-rate performance, delivering reversible capacities of 573 and 536 mA h g⁻¹ at 1 A g⁻¹, and 371 and 349 mA h g⁻¹ at 5 A g⁻¹, respectively. In this sense, our strategy may open the door to next-generation, high-power and high-energy anode materials for lithium-ion batteries.