Zr substitution aided enhancement of pseudocapacitive behavior of ceria

The scales at which energy storage is required, to enable transition to a renewable energy economy, is truly formidable. This is, in fact, one of the most significant challenges to the movement towards a sustainable future. Hence working with well distributed (even earth abundant) materials for energy storage is reasonable. Ceria is among the rare earth oxides that are rather well distributed; furthermore, it also shows promising redox behavior. However, there is an obvious need for improving its supercapacitive behavior. Here, we explore the role of isovalent (4+) substitution of Zr to enhance the supercapacitive behavior of ceria (CeO2). This is the first report on the effect of Zr-incorporation in ceria on Ni-foam for supercapacitors. Electrochemical study demonstrates ~16.5% increase in maximum specific capacitance and ~17% increase in energy density for Zr-incorporated ceria (Ce0.9Zr0.1O2) compared to its undoped counterpart in 2 M KOH electrolyte. Importantly Ce0.9Zr0.1O2 exhibits high cyclic stability of 93% after 2000 charge-discharge cycles at a high current density of 10 A g−1.