Enhanced sodium storage capability enabled by super wide-interlayer-spacing MoS2 integrated on carbon fibers

Developing advanced electrode materials for effective pseudocapacitive charge storage is one of effective strategies to enhance the rate capability and cycling stability of sodium ion storage devices. Herein, we fabricate MoS2 nanoflowers with super wide interlayer spacing (nearly twice as large as that of the original MoS2) supported on carbon fibers (named as E-MoS2/carbon fibers) and demonstrate its superior electrochemical performances as flexible and binder-free anodes for sodium-ion batteries (SIBs) and sodium-ion hybrid capacitors (SIHCs). Grafting MoS2 nanoflowers onto the carbon fiber networks not only ensures the fast electron transfer, but also endows it with flexible feature. The super wide interlayer spacing of MoS2 nanoflowers can not only decrease the ion diffusion pathways and resistance, but also increase their available and accessible active surface area, thus guaranteeing the rapid mass transport. Also, it can accommodate the large internal strain during discharge/charge processes. Benefiting from these combined structure merits, the E-MoS2/carbon fibers electrodes deliver an ultralong cycling stability up to 3000 cycles and the superior rate capacity of 104 mA h g(-1) at 20 A g(-1), which just takes ca. 18.7 s to fully charge/discharge. When further employed as the anode for SIHCs, it delivers high energy and power densities due to the high pseudocapacitive charge storage of the super wide interlayer spacing E-MoS2/carbon fibers.