Premium
Effect of the Electrolyte Alkaline Ions on the Electrochemical Performance of α‐Ni(OH) 2 /Activated Carbon Composites in the Hybrid Supercapacitor Cell
Author(s) -
Soserov L.,
Boyadzhieva T.,
Koleva V.,
Girginov Ch.,
Stoyanova A.,
Stoyanova R.
Publication year - 2017
Publication title -
chemistryselect
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.437
H-Index - 34
ISSN - 2365-6549
DOI - 10.1002/slct.201701579
Subject(s) - electrolyte , supercapacitor , electrochemistry , cyclic voltammetry , materials science , electrode , composite number , scanning electron microscope , chemical engineering , inorganic chemistry , composite material , chemistry , engineering
Hybrid electrochemical supercapacitors supply a high energy density and reduced cycle stability. Herein, we provide new data on the effect of the Li + and K + ion from the aqueous alkaline electrolyte on the hybrid supercapacitor performance. The electrochemical cell is assembled by two dissimilar electrodes: AC versus α‐Ni(OH) 2 /AC composite. Two types of alkaline electrolytes are used: individual KOH and mixed LiOH‐KOH solutions. The performance of the composite electrodes is tested by galvanostatic and cyclic voltammetry experiments. The Li + ions from the electrolyte display a positive effect on the discharge capacitance and the cycling stability of α‐Ni(OH) 2 /AC. The improved performance is discussed on the basis of structure and morphology changes of the composite electrode after electrochemical testing that are probed by ex‐situ X‐ray Diffraction, Scanning Electron Microscopy and Atomic‐force Microscopy. The results show that Li + ions and H 2 O from the LiOH‐KOH electrolyte are intercalated into α‐Ni(OH) 2 . The surface of the composite electrode becomes smoother in the mixed electrolyte. As a result, the α‐Ni(OH) 2 /AC displays an improved performance in the mixed LiOH‐KOH electrolyte than that in the individual KOH electrolyte.