A rational structural strategy to design rambutan-like NiFe-LDH nanocluster arrays electrode via a buffer-salt-assisted hydrothermal method was reported. For our developed electrode, large stable current density of 100 and 200 mA cm −2 at overpotential of only 283 and 300 mV in oxygen evolution reaction in alkaline electrolyte was obtained, which is dramatically lower than many previous reported overpotentials. It also exhibits low Tafel slope at current range from 10 to 25 mA cm −2 (56.47 mV dec −1 ). Further analysis demonstrates the key role of higher carriers of the rambutan-like NiFe-LDH nanocluster arrays electrode in boosting the water-splitting performance of the resulting system. Benefiting from the fine geometry shape of the self-supported nanocluster nanoarrays electrode, the transfer process of the reactants and oxygen/hydrogen bubbles is accelerated. In addition, a 19-time enhancement of carrier concentration for our developed rambutan-like NiFe-LDH nanoclusters (2.9 × 10 29  m −3 ) is obtained. Notably, the resultant rambutan-like NiFe-LDH nanocluster arrays electrode exhibits enhanced stability (in high and low current density) for the full water splitting in 1 M KOH, remaining nearly 100% of the original current density after continued testing for 20 h. This finding may provide new insight on rational structural design LDH nanostructures with high performance for electrocatalysis. Graphic abstract A highly hydrophilic NiFe-LDH nanocluster arrays electrode is developed for efficient full water splitting. Large and stable current density of 200 mA cm −2 is obtained at overpotential of 300 mV. Besides, the faraday efficiency is nearly 100%.