LAUSR

Abstract Copper benzene@1, 3, 5-tricarboxylate (Cu@BTC) metal organic frameworks with two mixed phases (Cu 3 (BTC) 2 ∙3H 2 O + {[Cu(BTC-H 2 ) 2 ∙(H 2 O 2 ]∙3H 2 O}) are synthesized in water solvent at different temperatures. The crystalline nature, porosity and morphology of prepared products are characterized by X-ray diffraction, Brunauer–Emmett–Teller surface analyzer and transmission electron microscope, respectively. The formation mechanism of these two mixed phases has been proposed, and the electrochemical measurements of the Cu@BTC MOFs are carried out for electrode material of supercapacitors. The Cu@BTC-120 electrode shows significant enhancement of specific capacitance compared with other Cu@BTC electrodes. A maximum specific capacitance of 228 F g −1 has been obtained at a current density of 1.5 A g −1 and long cyclic stability up to 3000 cycles with capacitance retention of ∼89.7% has been achieved for Cu@BTC-120 electrode. The fast transportation of the electrolyte ions in substantial voids space between octahedral micro-crystals (Cu 3 (BTC) 2 ∙3H 2 O) and micro-rods ({[Cu(BTC-H 2 ) 2 ∙(H 2 O 2 ]∙3H 2 O}) of Cu@BTC-120 has greatly improved the electrochemical performance.