Two-dimensional CoNi nanoparticles@S,N-doped carbon composites derived from S,N-containing Co/Ni MOFs for high performance supercapacitors

摘要: Due to their controllable morphologies, tunable porous structures, diverse compositions and easy fabrication, metal–organic frameworks (MOFs) are an ideal class of precursor material develop high performance carbon-based materials for energy applications. In this work, two-dimensional (2D) Co/Ni MOFs nanosheets with a molar ratio Co2+ Ni2+ 1 : 1 were first synthesized at room temperature using thiophene-2,5-dicarboxylate (Tdc) 4,4′-bipyridine (4,4′-Bpy) as organic linkers. As material, the as-synthesized 2D further pyrolized 550 °C in N2 atmosphere incorporate CoNi alloy nanoparticles into S, N-doped carbon (CoNi@SNC) surface area 224 m2 g−1, structure, good conductivity. Interestingly, it was found that can be directly used electrode supercapacitors, delivering specific capacitance 312 F g−1 1 A whereas CoNi@SNC derived from its supercapacitors exhibits much higher (1970, 1897 1730 1, 2, 5 respectively) long cycling life (retaining 95.1% value 10 after 3000 cycles) excellent rate capability charge/discharge current. Further, asymmetric supercapacitor device constructed positive active negative electrode, exhibiting density 55.7 W h kg−1 power 0.8 kW lifetime stability up 4000 charge–discharge cycles (capacitance retention ∼90.6%). The results demonstrate electrochemical activation-generated oxides/oxyhydroxides on alkaline electrolyte during measurements species CoNi@SNC-constructed supercapacitor. Additionally, collectively attributed relatively area, which is favourable exposure sites; promotes redox-related mass transport; combination graphitic carbon, functions electron collector improve transfer.