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• CoNi-LDH with a hierarchical hollow cage structure has been synthesized. • Two-step water-assisted coprecipitation method is utilized at room temperature. • The synergic effect of nickel nitrate adsorption on bimetallic CoNi-ZIF is optimized. • The assembled ASC supercapacitor device delivers excellent energy density, power density and cyclic stability. Single imidazolate framework-67 (ZIF-67) is commonly used as a template to prepare layered double hydroxides (LDHs) with specific morphology to improve the performance of materials. Herein, the Co2+ ion in ZIF-67 is partially substituted by Ni2+ to obtain the dodecahedron bimetallic imidazolate framework (CoNi-ZIF). Subsequently, using bimetallic CoNi-ZIF as the sacrificial template, CoNi-LDH hierarchical hollow cage structures with wrinkled nanosheet arrays are synthesized at room temperature and in aqueous solution by an inexpensive and environment friendly surfactant-free approach. The optimized etched CoNi-LDH4 has a maximum specific capacitance of 1877 F g−1 at a current density of 1 A g−1, and cycling stability of 99.89% after 5000 cycles, which is significantly better than that of ZIF-67 derived CoNi-LDH67 (1357 F g−1 at 1 A g−1, cycling stability of 73.35%). The asymmetric supercapacitor with CoNi-LDH4 as a cathode and activated carbon (AC) as anode has an energy density of 49.3 Wh kg−1 at 750 W kg−1 power output and stable cycling performance (capacity retention of 92.13% after 5000 cycles). This study shows the prospect of bimetallic CoNi-ZIF derived LDHs nanostructures prepared at room temperature and in aqueous solution to improve the performance and stability of supercapacitors. [ABSTRACT FROM AUTHOR]