Chlorine doping enables NaTi2(PO4)(3)/C excellent lithium ion storage performance in aqueous lithium ion batteries

NaTi2(PO4)(3-x)Cl-3x/C(x = 0.00, 0.05, 0.10, and 0.20) samples were prepared by sol-gel modus, and were used as anode for aqueous lithium ion battery. Cl doping on PO43- site demonstrates no significant effect on morphology and crystallo-graphic phase for NaTi2(PO4)(3). And it can obviously improve electrochemical properties of NaTi2(PO4)(3) electrode. Among all composites, NaTi2(PO4)(2.9)Cl-0.3/C (NC-Cl-30) shows the best electrochemical performance. NC-Cl-30 presents discharge capacity of 131, 100, and 79 mAh g(-1) at 0.2, 3.0, and 15C, separately, 55, 36, and 34 mAh g(-1) higher than those of original sample. In addition, discharge capacity of 76.1 mAh g(-1) for NC-Cl-30 is reserved, which is increased by 17.6 mAh g(-1) than that of original sample after 1000 cycles (6C). This work shows that Cl doping on PO43- site is an effective way to promote the electrochemical performance of NaTi2(PO4)(3).