Sodium-ion battery (SIB) is an ideal device that could replace lithium-ion battery (LIB) in grid-scale energy storage system for power because of the low cost and rich reserve of raw material. The key challenge lies in developing electrode materials enabling reversible Na
+ insertion/desertion and fast reaction kinetics. Herein, a core-shell structure, FeS
2 nanoparticles encapsulated in biphase TiO
2 shell (FeS
2@TiO
2), is developed towards the improvement of sodium storage. The diphase TiO
2 coating supplies abundant anatase/rutile interface and oxygen vacancies which will enhance the charge transfer, and avoid severe volume variation of FeS
2 caused by the Na
+ insertion. The FeS
2 core will deliver high theoretical capacity through its conversion reaction mechanism. Consequently, the FeS
2@TiO
2 nanorods display notable performance as anode for SIBs including long-term cycling performance (637.8 mA·h·g
-1 at 0.2 A·g
-1 after 300 cycles, 374.9 mA·h·g
-1 at 5.0 A·g
-1 after 600 cycles) and outstanding rate capability (222.2 mA·h·g
-1 at 10 A·g
-1). Furthermore, the synthesized FeS
2@TiO
2 demonstrates significant pseudocapacitive behavior which accounts for 90.7% of the Na
+ storage, and efficiently boosts the rate capability. This work provides a new pathway to fabricate anode material with an optimized structure and crystal phase for SIBs.
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