Ultrathin NiCo-MOF Nanosheets for High-Performance Supercapacitor Electrodes

Metal–organic frameworks (MOFs) have attracted intensive attention for high-performance supercapacitors owing to their large specific surface area and tunable pore structure. Herein, ultrathin NiCo-MOF nanosheets are fabricated by a facile ultrasonication at room temperature and employed as a supercapacitor electrode material. The unique nanosheet-like structure of NiCo-MOF provides more electroactive sites and a shorter pathway for electron transfer and electrolyte diffusion, resulting in excellent electrochemical performance with a high specific capacitance of 1202.1 F g–1 at 1 A g–1. In addition, an asymmetric supercapacitor of NiCo-MOF//activated carbon was assembled in 2 M KOH electrolyte. It delivers an energy density of 49.4 W h kg–1 at a power density of 562.5 W h kg–1 in a voltage window of 1.5 V. The results demonstrate a new method to fabricate ultrathin MOF nanosheets for high-performance supercapacitor electrode materials.