Rare-earth gallium garnet (RE3Ga5O12, RE = Eu, Gd, Dy, Er, and Yb) self-assembled nanostructure based battery type electrodes for efficient asymmetric supercapacitor applications

Abstract

The modern energy crisis has recently prompted researchers to seek alternatives. In this context, using electrochemical energy resources for energy conversion and storage drew considerable interest. Herein, a new attempt at implementing a series of semiconducting rare earth gallium garnets (REGGs; RE = Eu, Gd, Dy, Er, and Yb)/RE3Ga5O12 is employed for energy storage application. Garnets, an active host for rare earth ions with significant physical and chemical features, are expected to be promising electrode materials for supercapacitors. REGGs are synthesized via the gel matrix method. The phase purity and morphology of synthesized garnets were confirmed using XRD, Raman, XPS, FESEM, and TEM analysis. All synthesized rare earth gallium garnets show a cubic structure and manifest coral reef-like structures with minor variations. The surface area of the material is calculated using BET analysis. The electrochemical performance of the material is evaluated with CV, GCD, and EIS analysis in 3 M KOH. Eu3Ga5O12 exhibits a notable specific capacity of 303 C g−1 (84.1 mA h g−1) at 1 A g−1 compared to other rare earth gallium garnets with sustained cyclic stability of about 80.12 % even after 5000 cycles. The practical applicability of the synthesized Eu3Ga5O12 material is investigated by analyzing its performance in asymmetric supercapacitor devices. The fabricated device exhibited a maximum energy and power density of 39.06 W h kg−1 and 1125 W kg−1 at 1 A g−1, respectively. The exquisite features of rare earth gallium garnets with extended electrochemical performance indicate their potential to be a promising electrode material for energy storage applications.