Synthesis of bimetallic CoNi-CoNiO2 nanoparticles embedded into mesoporous carbon as high-performance catalysts for supercapacitor electrode

Controlled integration of metal oxide/carbon structures for clean energy storage and conversion has drawn much attention in recent years. However, designing the metal oxide/carbon with high conductivity and good cycle durability still remains a challenge. Herein, we demonstrate a facile synthesis of bimetallic CoNi-CoNiO2 nanoparticles embedded into mesoporous carbon as electrode material (CoNi-CoNiO2-CMK-3) for supercapacitor. The mesoporous silica is used as the template, Ni(NO3)(2) and Co(NO3)(2) as the Ni2+ and Co2+ precursor, and sucrose as the carbon source. The molar ratio of Co2+ (Ni2+)/sucrose and pyrolysis temperatures are carefully screened. Combining the advantages of mesoporous carbon and the uniformly distributed CoNi-CoNiO2 particles, the composites exhibit well-defined capacitive features. Especially, the sample with 0.008 molar ratio of Co2+/sucrose and pyrolyzed at 800 degrees C display the highest capacitance up to 280 F g(-1) at 0.25 A g(-1) in 6 M KOH aqueous solution. In addition, 97.7% of the original capacitance is obtained after 10000 cycles. The high performance should be due to the fast ion-transport through mesoporous carbon and redox reaction on CoNi-CoNiO2 particles.