Ni(HCO₃)₂ nanosheet/nickel tetraphosphate (Ni(P₄O₁₁)) nanowire composite as a high-performance electrode material for asymmetric supercapacitors

Abstract

Nickel compounds, especially Ni(HCO3)2 (here denoted as NiC), have been widely combined with other materials to obtain composites with a more favorable structure that exhibit excellent electrochemical performance as supercapacitors. Unfortunately, the complicated processes for preparing such composites directly restrict their further application. Herein, we prepared a NiC/nickel tetraphosphate (Ni(P4O11)) nanocomposite (NiC/NiP) by introducing H 2 PO 4 − ions into the NiC reaction system; this composite can be applied in high-performance supercapacitors. The micromorphology of NiC/NiP material displayed an appropriate combination of NiP nanowires and thin NiC nanosheets, which provide sufficient active sites, short ion diffusion paths and fast ion diffusion speeds. NiC/NiP material exhibited an excellent rate performance of 70.2% retained capacity, although the current was increased by 15 times (1196 F g−1 at 2.0 A g−1 and 840 F g−1 at 30 A g−1). The energy density of a NiC/NiP//active carbon (AC) asymmetric supercapacitor fabricated in 6 M KOH was as much as 39.02 W h kg−1 and 26.67 W h kg−1 under corresponding power densities of 160 W kg−1 and 8000 W kg−1, respectively. The asymmetric supercapacitor delivered a stable cyclic performance of 78% capacitive retention after 5000 continuous charge/discharge cycles. More importantly, a 2.5 V light-emitting diode was lit successfully by two NiC/NiP//AC asymmetric supercapacitors in series. These results confirm that NiC/NiP nanocomposite has great potential in practical applications of electrochemical energy storage devices.

Advanced three-dimensional hierarchical porous α-MnO2 nanowires network toward enhanced supercapacitive performance

“…The electrode materials of current commercial supercapacitors are mainly carbon-based materials that based on electric double layer capacitance, which has low energy density. In recent years, pseudo-capacitor with high specific capacitance has attracted wide attentions [5][6][7][8]. Among the pseudo-materials, MnO 2 has excellent electrochemical properties, low cost, abundance and eco-friendly nature, and is becoming one of the most promising candidate materials for supercapacitors [9][10][11][12][13].…”

High performance asymmetric supercapacitor based on vertical nanowire arrays of a novel Ni@Co–Fe LDH core@shell as negative and Ni(OH)2 as positive electrode

“…The transition metals like Ir, Ru, Zn, Ni, Mn etc have been extensively investigated out of which, nickel is one of the most researched transition metals for various applications [11][12][13][14][15]. Moreover, 1D nanowires (organic as well as inorganic), because of their high surface area are very popular [16,17].…”