WSe2/Reduced Graphene Oxide Nanocomposite with Superfast Sodium Ion Storage Ability as Anode for Sodium Ion Capacitors

Sodium ion capacitors (SICs) represent a promising alternative of energy storage device with high energy/power densities as well as long life span. Exploration of novel anode materials with typically high rate performance is a shortcut to boost the performance of SICs. Here, we present a WSe2/reduced graphene oxide (rGO) nanocomposite synthesized by a home-made chemical vapor deposition (CVD) method. WSe2 nanoparticle is deposited uniformly at the surface of rGO nanosheets. The unique structure endows the composite with outstanding electrochemical properties. The specific capacity of 133.3 mAh g−1 at an ultrahigh current density of 60 A g−1 can be delivered. The sodium ion storage kinetics was investigated, exhibiting very high ratio of capacitive contribution during the sodium ion reaction process. The SICs based on the WSe2/rGO nanocomposite as anode show the maximum energy density of 42.8 W h kg−1 and maximum power density of 14.4 kW kg−1 as well as the superior cyclic stability, proving the promising of WSe2/rGO anode for SICs application.