Gd3+-doped NaTi2(PO4)3@C negative material with superior Na-storage property for sodium-ion batteries.

• The carbon coating and Gd3+-doping were simultaneously applied to promote the electrical conductivity of NaTi 2 (PO 4) 3 via a simple sol-gel approach. • The electronic conductivity of NaTi 2 (PO 4) 3 anode was greatly improved by the carbon coating and Gd3+-doping. • The Gd3+-doped NaTi 2−x Gd x (PO 4) 3 @C nanocomposites presented superior high-rate capabilities for sodium energy storage. [Display omitted] The pristine NaTi 2 (PO 4) 3 negative electrode material has a poor electrical conductivity, which significantly inhibits its application in sodium-ion batteries. Herein, carbon coating and Gd3+ doping are simultaneously applied to promote the electrical conductivity of NaTi 2 (PO 4) 3 through a simple sol-gel approach. The conductive carbon coating promotes apparent conductivity, while Gd3+-doping effectively improves intrinsic conductivity. Therefore, the resulting Gd3+-doped NaTi 2−x Gd x (PO 4) 3 @C (x=1%, 3%, 5%, 7%) composites display superior high-rate capabilities for sodium energy storage. A typical obtained NaTi 1.95 Gd 0.05 (PO 4) 3 @C anode presents high capacities of 105.9 and 93.1 mAh g−1 at 5 and 10 C, respectively. Furthermore, this anode shows a high capacity retention ratio of 95.2% at 20 C over 500 cycles. These results suggest that this carbon coating and doping strategy is highly effective and can be adopted to enhance the battery properties of other electrode materials. [ABSTRACT FROM AUTHOR]