Advanced Carbon–Nickel Sulfide Hybrid Nanostructures: Extending the Limits of Battery-Type Electrodes for Redox-Based Supercapacitor Applications

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High Resolution Image Download MS PowerPoint Slide Transition-metal sulfides combined with conductive carbon nanostructures are considered promising electrode materials for redox-based supercapacitors due to their high specific capacity. However, the low rate capability of these electrodes, still considered “battery-type” electrodes, presents an obstacle for general use. In this work, we demonstrate a successful and fast fabrication process of metal sulfide–carbon nanostructures ideal for charge-storage electrodes with ultra-high capacity and outstanding rate capability. The novel hybrid binder-free electrode material consists of a vertically aligned carbon nanotube (VCN), terminated by a nanosized single-crystal metallic Ni grain; Ni is covered by a nickel nitride (Ni 3 N) interlayer and topped by trinickel disulfide (Ni 3 S 2, heazlewoodite). Thus, the electrode is formed by a Ni 3 S 2 /Ni 3 N/ [email protected] architecture with a unique broccoli-like morphology. Electrochemical measurements show that these hybrid binder-free electrodes exhibit one of the best electrochemical performances compared to the other reported Ni 3 S 2 -based electrodes, evidencing an ultra-high specific capacity (856.3 C g –1 at 3 A g –1 ), outstanding rate capability (77.2% retention at 13 A g –1 ), and excellent cycling stability (83% retention after 4000 cycles at 13 A g –1 ). The remarkable electrochemical performance of the binder-free Ni 3 S 2 /Ni 3 N/ [email protected] electrodes is a significant step forward, improving rate capability and capacity for redox-based supercapacitor applications.