Reduced graphene oxide and Fe2(MoO4)3 composite for sodium-ion batteries cathode with improved performance

• Fe2(MoO4)3@reduced graphene oxide composite have been synthesized by hydrothermal method.
• The obtained materials reveal large discharge capacity, outstanding rate performance and good stability.
• The enhancement mechanism was explored.

Fe2(MoO4)3@reduced graphene oxide (FMO@rGO) composite have been synthesized by precipitation-hydrothermal method. Herein, the graphene oxide in the present synthesis acts not only as baffles between particle and particle that helps to prevent the increase of particle size, but also as conductive networks after hydrothermal treatment, providing high electronic conductivity between particle and particle. The special surface area of the as-prepared materials significantly increases from 19.738 m2 g−1 (FMO) to 51.401 m2 g−1 (FMO@rGO), which undoubtedly provide more interface area between the active materials and the electrolyte. As a cathode material for sodium-ion batteries, the FMO@rGO composite delivers high discharge capacity at 0.5 C, which is comparable to theoretical capacity and literatures, and impressive rate performance. As the current density is at 5 C, for the first time, the initial specific capacity of FMO@rGO composite is about 68.2 mAh g−1, and it remains 56.5 mAh g−1 after 100 cycles, of which the excellent electrochemical performance is mainly attributed to good conductivity, high specific surface area and significantly enhanced diffusion coefficient.