Hierarchical Cu2S@NiCo-LDH double-shelled nanotube arrays with enhanced electrochemical performance for hybrid supercapacitors

Abstract

Hierarchical nanotube arrays with complex shell structures are attractive for applications in electrode materials for effectively boosted electrochemical performance, but the construction of such delicate architectures with excellent electrochemical performance is very challenging. Herein, double-shelled nanotube arrays of hierarchical Cu₂S@nickel–cobalt layered double hydroxide (Cu₂S@NiCo-LDH DSNAs) are synthesized on a Cu foam (CF) substrate with a sequential multi-step strategy, and an integrated electrode is constructed with the nanostructured material. Benefiting from the unique hollow structure and the sophisticated assembly of different nano-sized subunits, the as-prepared hierarchical Cu₂S@NiCo-LDH DSNA electrode exhibits excellent electrochemical performances with a high mass loading of 5.0 mg cm⁻², including a high specific capacity of 2.8 mA h cm⁻² (20.4 F cm⁻², 555.6 mA h g⁻¹) at 4 mA cm⁻² and remarkable rate capability with 87% capacity retention at 40 mA cm⁻². Furthermore, a quasi-solid-state hybrid supercapacitor (HSC) is assembled with the Cu₂S@NiCo-LDH DSNAs and metal–organic framework (MOF)-derived nanoporous carbon (NPC) as the electrodes, exhibiting a high energy density of 1.67 mW h cm⁻² at the power density of 4.25 mW cm⁻².