Significantly enhanced electrochemical performance of lithium titanate anode for lithium ion battery by the hybrid of nitrogen and sulfur co-doped graphene quantum dots

•We reported a new lithium titanate/nitrogen and sulfur co-doped graphene quantum dots hybrid•The synthesis creates a crystalline interconnected porous framework composed of nanoscale LTO•The unique architecture achieves to maximize the rate performance and enhance the power density•Introduction of N,S-GQDs greatly enhances the electron transfer and the storage lithium capacity•The hybrid anode provides an excellent electrochemical performance for lithium-ion batteries

ABSTRACTThe paper reported a facile synthesis of lithium titanate/nitrogen and sulfur co-doped graphene quantum dots(LTO/N,S-GQDs). Tetrabutyl titanate was dissolved in tertbutanol and heated to refluxing state by microwave irradiation. Then, lithium acetate was added into the mixed solution to produce LTO precursor. The precursor was hybridized with N,S-GQDs in ethanol. Followed by drying and thermal annealing at 500 °C in Ar/H2 to obtain LTO/N,S-GQDs. The synthesis creates fully crystalline interconnected porous framework composed of nanoscale LTO crystals. The unique architecture achieves to maximize the high-rate performance and enhance the power density. More importantly, the introduction of N,S-GQDs don't almost influence on the electrolyte transport, but greatly improve the electron transfer and the storage lithium capacity. The LTO/N,S-GQDs anode exhibits remarkably enhanced electrochemical performance for lithium ion battery. The specific discharge capacity is 254.2 mAh g−1 at 0.1C and 126.5 mAh g−1 at 10C. The capacity remains 96.9% at least after 2000 cycles at 2C. The battery performance is significantly better than that of pure LTO electrode and LTO/graphene electrode.

Graphical abstractThe study reported a facile synthesis of Li4Ti5O12/nitrogen and sulfur co-doped graphene quantum dots (LTO/N,S-GQDs). The unique architecture and the introduction of N,S-GQDs create both ultrafast electron transfer and electrolyte transport. The as-prepared LTO/N,S-GQDs anode provides prominent advantage of specific capacity, high-rate performance and cycle stability.Figure optionsDownload full-size imageDownload as PowerPoint slide