Synthesis and electrochemical performance of Li4Ti5O12/C composite by a starch sol assisted method

Li4Ti5O12/C composite anode materials were synthesized by a simple starch sol assisted method using TiO2-anatase and Li2CO3 as raw materials and soluble starch as carbon source. The influences of calcination temperature and starch amounts on the microstructure and electrochemical performance were systematically investigated. The samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and constant-current charge/discharge cycling tests. The results showed that the Li4Ti5O12/C composite with 10 wt.% starch synthesized at 800 °C for 6 h had homogeneous particle size distribution with an average particle size of 200–300 nm and exhibited the optimal electrochemical performance with specific discharge capacities of 168.5, 160.8, 155.1 and 141.8 mAh g− 1 at 0.2 °C, 1 °C, 2 °C and 5 °C rates, respectively, and satisfactory cycling stability. It could be attributed to the homogeneous ultrafine particles and in situ carbon coating, which enhanced the electronic conductivity and diffusion of lithium ions in the electrode.

Graphical abstractA soluble starch sol assisted method was employed to prepare Li4Ti5O12/C composites. It is found that both the calcination temperature and starch amount have great influences on the structure and electrochemical performance of the composite. The phase-pure sample with 10 wt.% starch synthesized at 800 °C shows the optimal electrochemical performance, due to homogeneous particle size distribution with smaller particle size and enhanced electronic conductivity caused by the uniform carbon coating.Figure optionsDownload full-size imageDownload as PowerPoint slideHighlights► A simple starch sol assisted method was adopted to prepare Li4Ti5O12/C composite. ► The method leads to the uniform distribution of carbon coating on Li4Ti5O12 particle. ► There exist optimal calcination temperature and starch amount for good properties.