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