Boosting the lithium storage performance of Na₂Li₂Ti₆O₁₄ anodes by g-C₃N₄ modification

Na2Li2Ti6O14 particles were prepared by a simple solid-state process, and then g-C3N4-coated Na2Li2Ti6O14 composites were constructed by a facile solution route for the first time. The g-C3N4-coated Na2Li2Ti6O14 multicomponent composites because of their unique architecture as negative materials for Li-ion batteries can be expected to exhibit a significantly improved cycling stability and reversible capacity even at high rates. g-C3N4 (5 wt%)-coated Na2Li2Ti6O14 shows a discharge (charge) capacity of 184.4 (184.3) mA h g-1 at 500 mA g-1 after 100 cycles, which is larger than that of pristine Na2Li2Ti6O14 with a discharge (charge) capacity of 122.8 (122.0) mA h g-1. The use of g-C3N4 with a carbon framework containing abundant nitrogen provides more active sites and surface defects for redox reactions and Li-ion transport. The g-C3N4 coating decreases the impedance between the electrolyte and Na2Li2Ti6O14 and enhances the charge transfer, ionic conductivity and diffusion ability of Li ions of Na2Li2Ti6O14. This work offers an efficient way to design high-performance Na2Li2Ti6O14-based materials for advanced lithium ion battery, and g-C3N4 (5 wt%)-coated Na2Li2Ti6O14 shows an enormous potential as a negative material for next generation Li-ion batteries with excellent performance.