CeO2 nanosheets for high performance aqueous battery systems

Abstract

CeO₂ is a promising candidate as electrodes for aqueous battery systems, however, the bulk particles show rapid capacity fading. This work prepares CeO₂ nanosheets via a rapid microwave heating route in 10 min. Benefitting from the unique two-dimensional structure and rich oxygen vacancies, the assembled CeO₂ nanosheets electrode delivers a high initial discharge/charge capacity of 706.1/485.0 mAh g⁻¹ at 120 mA/g, a good reversible capacity of 182.4 mAh g⁻¹ remains after 400 cycles, superior rate capability (91.1 mAh g⁻¹ at 480 mA/g), as well as a fast diffusion kinetics (7.8 × 10⁻¹² cm² S⁻¹) for aqueous Zn-ion batteries (AZIBs). Capacitance fading issue has been greatly addressed compared to the reported bulk particles. Also, it exhibits a high specific capacitance of 436.8 F/g at 1 A/g, a long capacitance retention (98.9 % @ the 2nd cycle) after 5000 cycles at 2.0 A/g, a high energy density of 92.4 Wh kg⁻¹ at a power density of 107 W kg⁻¹ for supercapacitors (SCs).