3D flower-like molybdenum disulfide modified graphite felt as a positive material for vanadium redox flow batteries.

3D flower-like molybdenum disulfide microsphere modified graphite felt (MoS/GF) with excellent electrocatalytic activity and redox reversibility for the VO/VO couple is successfully fabricated by a facile hydrothermal method. The results show that the hydrothermal reaction time has a deep influence on the MoS structure; an open 3D flower-like MoS structure with a layer spacing of 0.63 nm is uniformly grafted on the GF surface for a reaction time of 36 h. With the presence of MoS, the total resistance (1.58 Ω) and charge transfer resistance (0.01 Ω) of MoS/GF-36 are smaller than that of the heat treated GF (2.04 Ω and 11.27 Ω, respectively), indicating that the electrode has better conductivity and more favorable electron transfer ability. As expected, a significant increase in the capacity and energy efficiency is obtained with the MoS/GF-36 electrode. These satisfactory results are attributed to the 3D flower-like structure on the surface of the electrode, which increases the contact area between the electrode and the electrolyte. More importantly, the MoS/GF electrode with excellent stability has great application prospect in vanadium redox flow batteries (VRFBs).