N-doped carbon coated LiTi2(PO4)3 as superior anode using PANi as carbon and nitrogen bi-sources for aqueous lithium ion battery

N-doped carbon coated LiTi2(PO4)(3) composites were synthesized by polyaniline (PANi) as carbon and nitrogen bi-sources, and used as anode for aqueous lithium ion battery (ALIB). High-quality N-doped carbon layers were achieved to modify LiTi2(PO4)(3) crystal. ALIB using as-synthesized LiTi2(PO4)(3)@C-N as anode exhibited superior rate performance. It delivered discharge capacities of 122.4, 105.8, and 95.3mAh g(-1) at rates of 0.2, 10, and 20C, respectively, much higher than those (97.4, 61.1, and 43.9mAh g(-1)) of LiTi2(PO4)(3) /C using sucrose as carbon source. Furthermore, LiTi2(PO4)(3)@C-N anode demonstrated outstanding cycling performance with a capacity retention of 82.1% after 1000 cycles at 2C, while only 56.3% of capacity retention was kept for that using sucrose as carbon source. The excellent electrochemical performances of LiTi2(PO4)(3)@ C-N are mainly attributed to good dispersion, proper carbon layer, and nitrogen doping, further accelerating the charge transfer and diffusion of Li ions/electrons. (C) 2018 Elsevier Ltd. All rights reserved.