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[Display omitted] • V-Ni@NiMoO 4 /Ni 12 P 5 with a microsphere structure as the supporting framework exhibits excellent cycling stability. • For OER, a low overpotential of only 254 mV is required to achieve a current density of 50 mA cm, with no significant decline observed after 114 h of cycling. • The introduction of phosphorus enhances the electron transfer at the Ni active sites, better activating adsorbates, and thus improving catalytic performance. At present, there are few reports on the micron-sized catalysts for overall water splitting. In this study, phosphating method were used to construct the self-supporting catalyst (V doped Ni microspheres coated by NiMoO 4 /Ni 12 P 5) with microspherical structure, providing a short path and a stable structure to guarantee quick electron transfer and excellent catalytic performance. Hence, oxygen evolution reaction (OER) only needs 254 mV to reach a current density of 50 mA cm−2 in 1.0 mol/L KOH, after 114 h without attenuation. The catalyst can achieve a current densitiy of 10 mA cm−2 with a voltage of only 158 mV for hydrogen evolution reaction (HER). When micron scale V-Ni@NiMoO 4 /Ni 12 P 5 is used as both anode and cathode for overall water splitting, the device can operate at a current density of 10 mA cm−2 for more than 200 h of good stability. Its superior catalytic performance can be attributed to the construction of micron size and phosphating. DFT calculations indicate that the introduction of P better activates the adsorbed *OH and H 2 O*, reduces reaction the energy barrier, and improves the catalytic activity. [ABSTRACT FROM AUTHOR]

The rational construction of the active materials with hierarchical structure is a feasible and effective strategy for realizing high electrochemical performance of supercapacitors. Herein, ultra-thin nickel hydroxide nanosheets are directly grow on the external surface of Ni 3 S 2 nanorod arrays grew on nickel foam through simple hydrothermal ways to form Ni 3 S 2 /Ni(OH) 2 hierarchical nanoarrays. The Ni 3 S 2 nanorod arrays synthesized on nickel foam using hydrogen peroxide as an inducer could not only serve as the main channel for charge transport but also support the growth of active materials, moreover, the exposed active parts can also participate in the electrochemical energy storage process. The external ultra-thin nickel hydroxide nanosheets augment the contact region with the electrolyte and enrich the electrochemical active sites. The Ni 3 S 2 /Ni(OH) 2 composite exhibits wonderful electrochemical performance is on account of its hierarchical structure could augment the effective specific surface area of electrode materials and induce a synergistic effect between each component. The aquaired Ni 3 S 2 /Ni(OH) 2 electrode presents a brilliant specific capacitance (826 ​C ​g−1 during 1 ​A ​g−1) and relatively good rate performance (50% retention during 20 ​A ​g−1). In addition, our prepared hybrid supercapacitor used Ni 3 S 2 /Ni(OH) 2 and AC acted as cathode and anode, respectively, gives rise to a superior energy density of 48.3 ​Wh kg−1 at about 800 ​W ​kg−1 of power density, together with retained about 70% capacitance after 10000 cycles at 5 ​A ​g−1. Meanwhile, two hybrid supercapacitor devices were fabricated in series to power a white LED, which can be continuously lit for more than 8 ​min. Herein, ultra-thin Ni(OH) 2 nanosheets are directly grow on the surface of Ni 3 S 2 nanorod arrays supported on nickel foam. Two Ni 3 S 2 /Ni(OH) 2 //AC hybrid supercapacitor devices can lighten a white LED for more than 8 ​min. [Display omitted] • The ultra-thin nanosheets combined with nanorod arrays structure enhance electrochemical performances. • A simple two-step hydrothermal method is developed. • Two Ni 3 S 2 /Ni(OH) 2 //AC hybrid supercapacitors in series can power a white LED for more than 8 ​min.. [ABSTRACT FROM AUTHOR]