Sacrificial Nanowire Catalyzed Polymerization Process Generates Hierarchical MoSe₂ Grafted Carbonaceous Nanotubes for Superior Potassium Ion Storage

Sodium/potassium ion based hybrid capacitors have recently attracted tremendous attention owing to their unique features of combining high-energy battery and high-power capacitor, as well as lower cost compared to Li+ based energy storage techniques. However, the exploitation of promising anode candidates featuring both high specific capacity and fast charge/discharge capability remains an urgent task. Herein, we present a promising anode host composed of MoSe2 grafted carbonaceous nanotubes (denoted as MoSe2-G-CNTs) through a sacrificing nanowire catalyzed polymerization process followed by conventional selenization treatment. The resultant MoSe2-G-CNTs exhibit a superior K+ storage capability with a high reversible capacity (321.7 mAh g–1 at 0.1 A g–1) and long cycling stability (188 mAh g–1 after 2000 cycles at 1.0 A g–1). The possible origins of the remarkable performance are unraveled on the basis of the in situ Raman spectrum and galvanostatic intermittent titration (GITT) techniques. Importantly, the potassium ion hybrid capacitors (KIHCs) based on MoSe2-G-CNTs anode can deliver a decent energy density of 109.8 Wh kg–1 at a power density of 462.3 W kg–1 with a long lifespan up to 6000 cycles. This work could not only provide a design rationale for advanced hybrid nanostructures but also steer the boom of energy storage devices based on earth-abundant alkaline metals.