Self-enhanced electrochemical properties of Ni–P nanosphere with heterogeneous Ni and Ni–P nanoflake outer layer anchored on carbon cloth for asymmetric all-solid-state supercapacitors

• Published in: Journal of materials science. Materials in electronics Vol. 30; no. 19; pp. 18088 - 18100
• Main Authors: Ling, Jingzhou, Zou, Hanbo, Yang, Wei, Lei, Kangzhou, Chen, Shengzhou
• Format: Journal Article
• Language: English
• Published: New York Springer US 01.10.2019; Springer Nature B.V
• Subjects: Asymmetry; Carbon; Characterization and Evaluation of Materials; Chemistry and Materials Science; Cloth; Core-shell structure; Dealloying; Electrochemical analysis; Flux density; Ion diffusion; Materials Science; Morphology; Nanospheres; Optical and Electronic Materials; Organic chemistry; Retention; Solid state; Supercapacitors; Surface layers
• ISSN: 0957-4522; 1573-482X
• DOI: 10.1007/s10854-019-02162-7

To meet the demand for high-power-density and long lifespan surpercapacitors (SCs), the Ni–P@Ni HL/CC-1h with a core–shell structure (Ni–P sphere as the core and nanoflake with the Ni and Ni–P heterogeneous layer as shell) was constructed via a facile strategy. The strategy included hydrothermal synthesis of Ni–P spheres with large Ni surface layer on carbon cloth (Ni–P@Ni HL/CC) and subsequent chemical dealloying using HCl as etching solution in order to remove the redundant Ni substances. The morphology, composition, and electrochemical performances of raw Ni–P@Ni HL/CC and the corresponding samples obtained by different dealloying times (0.5, 1, and 2 h) were characterized. Interestingly, the Ni–P@Ni HL/CC-1h presents a unique structure with a nanoflake shell and a porous core, which can provide a large number of exposed active sites, accelerate electrolyte ion diffusion and support ultra-long cycling. Furthermore, the Ni species existing in the outer flake can increase the conductivity and promote the capacitance during the charge–discharge processes. The Ni–P@Ni HL/CC-1h exhibited high specific capacity of 280.8 C g −1 at current density of 1 mA cm −2 , high rate retention of 76.2% at 20 mA cm −2 . The maximum specific capacity could reach 388.8 C g −1 at 8 mA cm −2 , and maintained the 92.6% retention after 3000 cycles. Moreover, the Ni–P@Ni HL/CC-1h//AC all-solid-state asymmetric supercapacitor (ASC) exhibited high specific capacity, 86.0% retention after 10,000 cycles and high energy density of 27.6 Wh kg −1 at power density of 942.8 W kg −1 .