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 m

A·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.