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.