Amorphous carbon coated TiO2 nanocrystals embedded in a carbonaceous matrix derived from polyvinylpyrrolidone decomposition for improved Li-storage performance

Abstract

A facile method has been developed for the fabrication of TiO2-C nanocomposite anode material, where a thin amorphous carbon layer is coated on the surface of TiO2 nanocrystals for lithium-ion batteries (LIBs) application. To study the structure–property correlations, the effects of different carbon content and nanocrystals size of nanocomposites on the electrochemical properties of LIBs are systematically studied by post-calcination at various temperatures. Based on detailed experimental results, it is demonstrated that amorphous carbon-coated TiO2 nanocrystals calcinated at 400°C show the best electrochemical performance as compared with its counterparts at 500°C and 600°C. At 400°C, the enhanced electronic conductivity from the decomposition of polyvinylpyrrolidone (PVP) seems to be the main reason for the improved capacity of TiO2 nanocrystals-based LIBs. This unique architecture of anodes materials provides many important features for high-performance LIBs, such as fast ion transport and relatively high electrical conductivity, thus leading to the outstanding electrochemical performance of the electrodes. Such an electrode yields 228mAhg−1 capacity (1 C=170mAg−1) even after 100 cycles. This method is proven to be an effective technique for improving the electrochemical performance and stability of TiO2 based anode electrodes, especially for nanocrystal electrodes application in LIBs.