Morphology Engineering of Hybrid Supercapacitor Electrodes from Hierarchical Stem-like Carbon Networks with Flower-like MoS2 Structures

There is a critical need to develop high-performance supercapacitors that can complement and even rival batteries for energy storage. This work introduces a strategy to drastically enhance the energy storage performance of a supercapacitor by engineering electrode morphologies with ternary composites offering distinct benefits for the energy storage application. The electrodes were fabricated with conductive networks of carbon nanotubes (CNTs) coated with a zeolitic imidazole framework (ZIF) for high ion diffusivity and ion-accumulating molybdenum disulfide (MoS2) with various morphologies. These include flower-like (fMoS2), stacked-plate (pMoS2), and exfoliated-flake (eMoS2) structures from topochemical synthesis. CNT-ZIF-fMoS2 demonstrates an excellent energy density, reaching almost 80 Wh/kg, and a maximum power density of approximately 3000 W/ kg in a half-cell. This is far superior to the electrodes containing pMoS2 and eMoS2 and attributed to the increased surface area and the faradaic reactivity offered by fMoS2. Additionally, the CNT-ZIF-fMoS2 electrode demonstrates exceptional stability with an -,78% of capacitance retention over 10,000 cycles. This work suggests that the electrode morphologies can dominate the energy storage behaviors and that the heteromaterial approach may be crucial in designing next generation supercapacitors.