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 g^-1 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.