Influence factors on electrochemical properties of Li 4Ti 5O 12/C anode material pyrolyzed from lithium polyacrylate

Abstract

Spinel Li 4Ti 5O 12/C was synthesized by one-step solid-state reaction route using lithium polyacrylate (PAALi) as lithium and carbon sources, and TiO 2 as titanium source. The characteristics of Li 4Ti 5O 12/C composites were determined by X-ray diffraction, scanning electron microscopy, transmission electron microscopy and thermogravimetric-differential thermal analysis methods. Their electrochemical performances were investigated by cyclic voltammograms, constant current charge–discharge and rate charge–discharge. It was found that molecular weight of polyacrylic acid (PAA), heating rate and sintering duration directly affected the physical and electrochemical performances of Li 4Ti 5O 12/C composites. The Li 4Ti 5O 12/C composites with the optimized electrochemical performances were obtained in the following conditions, i.e., PAA with the molecular weight of 10,000, heating rate of 20 °C min −1 and sintering duration of 8 h. At charge–discharge rate of 4 C and 8 C, the optimized sample showed discharge capacities of 148.4 and 142.4 mAh g −1, with capacity retention of 94.48 and 90.53% after 50 cycles, respectively. Even at 20 C, its discharge capacity was 116.0 mAh g −1 with capacity retention of 87.61% after 50 cycles.