Nan Zhou,Shengxiong Huang,Tao Hong,Wei Luo,Yun Tian,Xiangyang Lu,Zhi Zhou
In this paper, LiTi 2 (PO 4 ) 3 @carbon composite as anode for aqueous lithium ion battery has been successfully synthesized by in-situ carbon coating method using oxalic acid and glucose as double carbon sources. XRD results confirm the rhombohedral NASICON-type LiTi 2 (PO 4 ) 3 structure of the as-prepared composite. The LiTi 2 (PO 4 ) 3 @carbon composite using double carbon sources (LTP-OG-10) disperses well, and the coated carbon layer has the appropriate thickness of 3–7 nm, which result in proper balance of the good electrical conductivity and the fast kinetics of diffusion of lithium ions . LTP-OG-10 exhibits better electrochemical performance compared with those using oxalic acid (LTP-O) or glucose (LTP-G) single carbon source. LTP-OG-10 anode delivers the discharge capacity of 112.5 mA h g −1 , 96.8 mA h g −1 , and 54.2 mA h g −1 at 0.2 C, 5 C and 20 C, respectively, much larger than that of LTP-O and LTP-G. Moreover, LTP-OG-10 demonstrated excellent cycling performance, with the capacity retention of 71.1% after 400 cycles at 0.2 C, 22.9% higher than that of LTP-G. The good electrochemical properties of LTP-OG-10 is mainly ascribed to the increase of defects, high-quality and appropriate thickness of carbon layer. Our study reveals that preparing LiTi 2 (PO 4 ) 3 @carbon composite using double carbon sources is an efficient approach to enhance its electrochemical properties.
In this study, a one-pot sintering process incorporating sol–gel preparation route and in-situ carbon coating was proposed for the synthesis of carbon-coated nanosized LiTi 2 (PO 4 ) 3 . Experimental results show that the prepared LiTi 2 (PO 4 ) 3 particles are of high crystallinity and well-coated by turbostratic carbon. Attributed to nanosized particles and enhanced conductivity provided by turbostratic carbon coating, the carbon-coated LiTi 2 (PO 4 ) 3 showed high rate performance and good cycling life in aqueous electrolyte. Particularly, the carbon-coated LiTi 2 (PO 4 ) 3 exhibited initial specific capacities of 103 and 89 mAh g −1 , and retained 80.6% and 97% of the initial capacities after 120 cycles at 1C and 10C in aqueous electrolyte, respectively. The high rate performance and good cycling life of carbon-coated LiTi 2 (PO 4 ) 3 in aqueous electrolyte reveal its potential as negative electrode in aqueous lithium-ion batteries for electric vehicles and industrial-scale energy storage systems .