Synthesis of nickel carbonate hydroxide/zeolitic imidazolate framework-8 as a supercapacitors electrode

The zeolitic imidazolate framework-8 (ZIF-8), nickel carbonate hydroxide (Ni2CO3(OH)(2)) and Ni2CO3(OH)(2)/ZIF-8 composite material are synthesized by a typical solvothermal method. In the Ni2CO3(OH)(2)/ZIF-8 material, the ZIF-8 acts as the host for the growth of Ni2CO3(OH)(2). Their structure and surface morphology are characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy and nitrogen adsorption-desorption isotherms. The porous structure combined with Ni2CO3(OH)(2) maximizes the utilization of active material, resulting in a high specific capacitance. As electrode materials for supercapacitors, the ZIF-8, Ni2CO3(OH)(2) and Ni2CO3(OH)(2)/ZIF-8 electrodes exhibit a specific capacitance of 140, 668 and 851 F g(-1) respectively at a scan rate of 5 mV s(-1) and good stability over 5000 cycles. In particular, Ni2CO3(OH)(2)/ZIF-8 is a promising candidate for the supercapacitor electrode.