Defect-rich CeO2 in a hollow carbon matrix engineered from a microporous organic platform: a hydroxide-assisted high performance pseudocapacitive material

Abstract

A microporous organic polymer (MOP) was utilized for the engineering of nanoparticulate CeO₂ in a hollow carbon matrix (H-C/CeO₂). After CeO₂ nanoparticles were incorporated into a hollow MOP platform (H-MOP) through the decomposition of cerium acetate, successive carbonization produced H-C/CeO₂. The redox feature of defective CeO₂ in a conductive carbon matrix induced promising pseudocapacitive behavior. In particular, the H-C/CeO₂ showed excellent electrochemical performance in an alkaline electrolyte (KOH), due to the hydroxide ion-assisted redox behavior of defective CeO₂. H-C/CeO₂-3 with an optimized amount of CeO₂ showed specific capacitances of up to 527 (@0.5 A g⁻¹) and 493 F g⁻¹ (@1 A g⁻¹). Even at high current densities of 10 and 20 A g⁻¹, the H-C/CeO₂-3 maintained high capacitances of 458 and 440 F g⁻¹, respectively. After 10 000 cycling tests, the H-C/CeO₂-3 retained the 94–95% capacitance of the first cycle.