Insights on Effect of Different Electrolytes on Electrochemical Performance of CoNi Nanoflower-Based Supercapacitors

Abstract

Bimetallic materials show superior properties over monometallic systems due to their synergistic effect. Herein, bimetallic CoNi nanoflowers are synthesized by a simple method and characterized via various characterization techniques such as powder X-ray diffraction (PXRD), scanning electron microscopy, high-resolution transmission electron microscopy, X-ray photoelectron spectroscopy, etc. PXRD results confirm the formation of face-centered cubic CoNi nanoflowers and morphological studies confirm the flower-like structure of CoNi. Bimetallic CoNi nanoflowers utilized for supercapacitor applications and the effect of electrolyte cations (K+, Na+, Li+) are studied. The results reveal that LiOH shows excellent capacitance of 729.52 F g−1 (66.83 mAh g−1) at 1 A g−1. The cyclic stability of CoNi nanoflower is estimated as ≈100% after 10 000 cycles which signifies the exceptional long-term utility of the electrode for practical application. Further, the asymmetric device is fabricated which shows the capacitance of 66.61 F g−1 and the commercial light-emitting diode (1.8 V) delivers high energy density and power density, that is, 18.13 Wh kg−1 at 699.84 W kg−1. The nanoflower exhibits battery–supercapacitor-type behavior with rapid charge/discharge capability with a binder-free and additive-free approach. © 2023 Wiley-VCH GmbH.