Optimizing the lithium storage property of sodium lithium titanate via oxygen-site doping

Two modified products of Na 2 Li 2 Ti 6 O 14 were prepared via O-site replacement by F − and Cl − doping and employed to store lithium during cycles. Through tests of structure and electrochemical properties, it seems that substituting part of the O-site for low-valent ions enables better ionic and electronic conductivities of pristine Na 2 Li 2 Ti 6 O 14 . As a consequence, the modified products exhibit preferable electrochemical performance when compared with the pristine one, especially for the Na 2 Li 2 Ti 6 O 13.7 F 0.3 , which displays the best reversible charge specific capacity of 121.20 mAh g −1 and the battery was tested at 100 mA g −1 . Moreover, in situ XRD results explain that the great reversibility of structure is significant to the excellent lithium storage property of Na 2 Li 2 Ti 6 O 13.7 F 0.3 for the rechargeable lithium-ion batteries. Graphical abstract