Low temperature synthesis of high electrochemical performance Co3O4 nanoparticles for application in supercapacitor

Nonaggregate and well-crystallized Co3O4 nanoparticles with size of 5-15 nm were prepared on a large scale at low temperature by an epoxide precipitation route. The preparation of Co3O4 nanoparticles followed the steps of alpha-Co(OH)(2) formation through epoxide precipitation reactions, conversion of alpha-Co(OH)(2) to CoOOH in ammonia regulated alkaline suspension, and transformation of CoOOH to Co3O4 at 100 degrees C. The small size and nonaggregate state of obtained Co3O4 nanoparticles guaranteed the full contact of Co3O4 nanoparticles with electrolyte and the complete penetration of electrolyte into the particles. Consequently, the Co3O4 nanoparticles presented specific capacitance as high as 879.5 F g(-1) at scan rate of 5mV s(-1) in 1 KOH. Their specific capacitance remain 82.8% of the initial specific capacitance after 5000 charge and discharge cycles. These results demonstrated that these Co3O4 nanoparticles can be applied as a high performance electrode material for supercapacitor.