3D hierarchical mesoporous structure, micron-sized flowers composed of nickel carbonate hydroxide hydrate (Ni2(CO3)(OH)2·H2O) (NCH) nanopetals were successfully synthesized by single-step facile hydrothermal method. The processing parameters appears to play vital role in governing nano-petaled flowers, provides high electroactive surface area. The mesoporous structure of 3D hierarchical structure offers a specific capacity of 353 mAh/g at a scan rate of 1 mV/s and ∼245 mAh/g under the current density of 1.83 A/g, respectively. The material has outperformed during the cycling stability when tested for the moderate and highest current density of 20 A/g and 40 A/g, respectively; it retained excellent capacity retention of ∼80% and 64%, respectively. The electrochemical impedance spectroscopy analysis was employed to probe the charge-transfer kinetics and charge storage performance and found to be in correlation with other charge storage analysis. The outstanding electrochemical performance is accredited to the intrinsic nature of nanostructured NCH, forming a unique miro-3D flower-like morphology. This ingenious synthesis strategy resulted in overall excellent electrochemical properties; indicating the NCH is a potential candidate for high-performance battery-like energy storage applications.