A phosphatized NiCo LDH 1D dendritic electrode for high energy asymmetric supercapacitors.

Constructing orderly nanostructures and modifying surfaces are two important ways to improve the electrode materials of supercapacitors. Herein, 1D dendritic P@NiCo LDH electrode materials were successfully synthesized via phosphatizing a treated Ni/Co hydroxide precursor. We noticed that the 4M-P@NiCo LDH (with 40 mmol of reactant/75 mL for 6 cm2 of Ni foam) exhibited high areal capacitance of 7 F cm-2 at 50 mA cm-2 in a 6 M KOH three-electrode aqueous electrolyte system, which is about 4 times as much as before phosphatization. Also, a 4M-P@NiCo LDH//AC asymmetric supercapacitor obtained a high energy density of 18.1 W h kg-1 at 750 W kg-1 and showed excellent capacity retention of 77.17% after 5000 cycles at a 10 A g-1 current density, indicating its great application potential.