Ionic Liquid-Assisted Exsolution of High-Density Cu Nanoparticles on La1.568sr0.392ce0.04nicuxo4-Δ as Cathode for Zn-Air Batteries

Abstract

In-situ exsolution of metal nanoparticles (NPs) from perovskite-type oxides has sparked tremendous attention to design highly efficient and durable heterogeneous catalysts for energy applications. However, the numbers of exsolved metal NPs are still limited even at high temperatures in reducing environments due to the sluggish kinetics of cations. Herein, an ionic liquid-assisted voltage-driven exsolution strategy at room temperature to prepare the Cu NPs socketed on La1.568Sr0.392Ce0.04NiCuxO4-δ (Cu@LSCNC x , x=0.05, 0.1, 0.2) with uniform distribution and high density was proposed. When employed as cathodes for Zn-air batteries, the electrochemical performance was significantly enhanced, mainly ascribing to the rich well-dispersed Cu NPs, synchronously generated socketed metal/oxide interfaces and oxygen vacancies, which facilitated the mass transportation and electrons transferring during the charging/discharging process. Specifically, Cu@LSCNC0.05 , exsolved using 1-butyl-3-methylimidazolium iodide with an applied voltage of -0.6 V, demonstrated the highest peak power density enhancement of about 201% from 42.6 to 128.4 mW·cm-2 compared to the LSCNC0.05 counterpart. In addition, the battery performance could be enhanced under the solar irradiation. This work provides a new approach to designing economic and effective catalysts with abundant metal/oxide interfaces for many challenging electrochemical applications.

Keywords: Ionic liquid, Voltage-driven, Exsolution, Cu nanoparticle, Zn-air battery