HF-Free Synthesis of Anatase TiO2 Nanosheets with Largely Exposed and Clean {001} facets and Their Enhanced Rate Performance As Anodes of Lithium-Ion Battery

An interface between toluene and water was utilized to synthesize ca. 10 nm thick of anatase TiO2 nanosheets (NSs) with 82% exposure of {001} facets. In this procedure, highly corrosive and toxic HF, which was generally used to prepare TiO2 NSs with largely exposed high energy facets, was avoided. Furthermore, the surfaces of the NSs were quite clean as suggested by XPS analysis. Serving as anode materials in lithium-ion batteries, these as-prepared anatase TiO2 NSs manifested a low initial irreversible capacity loss (12.5% at 1 C), an excellent capacity retention at 10 C charge discharge rate (101.9 mA h after 100 cycles), and enhanced rate performance at 0.5-10 C current rates in compared with Degussa P25 TiO2 nanoparticles (NPs). Their excellent electrochemical performances were mainly derived from the large proportion of {001} exposed facets and a very short diffusion pathway, which allowed fast and efficient Li+ transportation in the electrodes.