3D MoS/graphene oxide integrated composite as anode for high-performance sodium-ion batteries.

Sodium-ion batteries (SIBs) are emerging as a promising alternative to conventional lithium-ion technology, due to the abundance of sodium resources. The major drawbacks for the commercial application of SIBs lie in the slow kinetic processes and poor energy density of the devices. Molybdenum sulfide (MoS), a graphene-like material, is becoming a promising anode material for SIBs, because of its high theoretical capacity (670 mAh g) and layered structure that suitable for Na intercalation/extraction. However, the intrinsic properties of MoS, such as low conductivity, slow Na diffusion kinetics and large volume change during charging/discharging, restrict its rate capability and cycle stability. Here, molybdenum disulfide and graphene oxide (3D MoS/GO) with excellent conductivity were fabricated through layer-by-layer method using amino-functionalized SiO nanospheres as templates. The 3D MoS/GO composite demonstrates excellent cycling stability and capacity of 525 mA h g at 500 mA g after 100 cycles, which mainly due to the integrated MoS/GO components and unique 3D macroporous structure, facilitating the material conductivity and Na diffusion rate, while tolerating the volume expansion of MoS during the charge/discharge processes.