Porous graphitic carbon nitride improved Li4Ti5O12 anode material for lithium storage capacity

Designing nanocomposite materials with novel structures can effectively improve the electrochemical performance of lithium-ion batteries. In this paper, we synthesized porous graphitic carbon nitride (PCN) using the pyrolysis reaction of thiourea. Subsequently, we take advantage of the porous structure of PCN to homogeneously disperse Li4Ti5O12 (LTO) on the surface of PCN by hydrothermal and subsequent calcination and synthesize Li4Ti5O12/porous graphitic carbon nitride (LTO/PCN) nanocomposites. In this nanocomposite, PCN was used as the carrier, and Li4Ti5O12 was uniformly dispersed in the PCN. Due to the pores of PCN, the distribution of Li4Ti5O12 is more dispersed, which increases the specific surface area of composites and reduces the diffusion path of Li+. The sulfur element in PCN also helps to improve the electrical conductivity of the nanocomposites. The best properties of PCN nanocomposites were obtained when thiourea and melamine were calcined in a ratio of 1:4. The designed LTO/PCN shows superior high-rate performance for lithium-ion batteries. After 100 cycles at 0.5C, it still maintains a discharge capacity of 173.2 mAh/g. Even at a high current of 10C, LTO/PCN-4 maintains a discharge capacity of 128.9 mAh/g after 500 cycles. Our study provides a general method for the synthesis of high-performance LTO/PCN-4 nanocomposites. LTO nanoparticles were uniformly dispersed on PCN sheets by simple hydrothermal and calcination. In addition, because the distribution of LTO is more dispersed, the diffusion path of Li+ is greatly shortened, and the LTO/PCN nanocomposites have better rate performance and cycle performance. [Display omitted] •LTO/PCN nanocomposites is fabricated via a hydrothermal and calcination methods.•PCN acts as a carrier and reduced the diffusion path of Li+.•When PCN with thiourea to melamine ratio of 4:1 was selected, the electrochemical performance of the electrode was the best.•LTO/PCN-4 electrode possesses an exceptional rate performance of 186.4 mAh/g at 0.5C.•Even after 500 cycles at 10C, the discharge capacity maintains at 128.9 mAh/g.