Synthesis of copper/chromium metal organic frameworks- Derivatives as an advanced electrode material for high-performance supercapacitors

Highly optimized copper chromium mixed oxides, derived from mixed cupper/chromium metal organic frameworks (Cu/Cr-MOF), have been successfully synthesized by calcination of parent chromium metal organic frameworks (Cr-MIL-101), cupper metal organic frameworks (Cu-BDC), and mixed Cu/Cr-MOFs in air. The as -synthesized MOF derivatives (CuxCr(1-x)-MOF-D) were characterized using nitrogen adsorption desorption iso-therms (BET), SEM, EDX, TEM, XRD, XPS, SEM-elemental mapping, FT-IR, DSC and TGA analysis. XRD displayed that only one crystalline phase resulted for copper and chromium which is CuO and Cr2O3, respectively. The prepared MOF derivatives (MOF-D) displayed a regular octahedral morphology in case of Cr-MOF-D, which is changed to distorted octahedral structure after the addition of copper in the same frameworks, as confirmed by TEM and SEM techniques. Cu/Cr-MOF-D displayed exceptional electrochemical behavior for Cu0.50Cr0.50-MOF-D electrode with specific capacitance of 535.1 F. g-1 at 0.7 A. g-1 within potential window (Delta V) of 1.04 V. Also, it generated high power and energy density of 2600 W kg-1 and 36.7 W h kg-1, respectively. Cu0.50Cr0.50-MOF-D electrode has excellent cycling stability, that retained 90.3% of its initial specific capacitance even after 5000 cycles compared to the capacitance retention of Cu-MOF-D and Cr-MOF-D electrodes that reached 70.26% and 69.17%, respectively.

Automated summary

Highly optimized copper chromium mixed oxides were successfully synthesized from copper and chromium metal organic frameworks. The synthesized MOF derivatives exhibited regular octahedral morphology and exceptional electrochemical performance, with a specific capacitance of 535.1 F. g-1 and excellent cycling stability, retaining 90.3% of its initial capacitance after 5000 cycles.