Dual Function Metallo–Organic Assemblies for Electrochromic–Hybrid Supercapacitors

Abstract

An integrated electrochromic–hybrid supercapacitor (EHSC) is demonstrated; the device’s operation (charging–discharging) is indicated by optical changes (from colored to transparent). The heart of the device is an electrochromic metallo–organic layer that functions as both the battery‐type electrode and the charge indicator. The capacitive electrode is a layered composite of multiwalled carbon nanotubes (MWCNTs) and a conductive polymer (poly(3,4‐ethylenedioxythiophene) polystyrene sulfonate, PEDOT:PSS). The device operates under low potentials (−0.6 to 2 V), displays high energy and power densities (≈2.2 Wh kg−1 and ≈2529 W kg−1), a high coulomb efficiency (99%), a short charging time (≈2 s), and a charge retention (V½) of ≈60 min. Stability, both in color and energy, for more than 1000 consecutive charging–discharging cycles is demonstrated. No significant changes in device temperature are indicated under the operating conditions. The EHSC is wired with a conventional circuit board to be charged and subsequently to operate a diode. The results demonstrate the potential of metallo–organic assemblies for usage in these types of supercapacitors.

Probing the Influence of Counter Electrode Structure on Electrochromic‐Device Operating Potentials and Performance Using Electrochemical Impedance Spectroscopy

“…[8] Currently, ECMs are designed [9] using metal oxide films, [10][11][12] organic molecules, [7,13] organic conjugated conductive polymers, [14] and metal-coordination complexes. [15][16] Among the others, ECDs based on polypyridine metal-coordination complexes demonstrate enhanced cyclic stability, short switching times and exceptional coloration efficiency. Previously, it was demonstrated that 2,2':6',2''terpyridine (terpy) moiety can form stable complexes with a variety of metals in different oxidation states.…”

“…Several parameters must be met for an ECM to be a viable candidate for commercial applications, these include high contrast ratios, coloration efficiency, cyclic durability and short switching times [8] . Currently, ECMs are designed [9] using metal oxide films, [10–12] organic molecules, [7,13] organic conjugated conductive polymers, [14] and metal‐coordination complexes [15–16] . Among the others, ECDs based on polypyridine metal‐coordination complexes demonstrate enhanced cyclic stability, short switching times and exceptional coloration efficiency.…”

Novel poly(1H‐benzo[g]indole)/TiO2 nanocomposites for high‐performance electrochromic supercapacitor application

“…Cai et al prepared Fe(II)‐based metal supramolecular polymer films by molecular assembly strategies, which showed significant electrochromic properties and strong stability 19 . Eisenberg et al used iron polypyridyl complexes as battery‐type electrode and poly(3,4‐ethylenedioxythiophene) Polystyrene sulfonate (PEDOT:PSS) as capacitive electrode to prepare integrated metallo‐organic electrochromic supercapacitors 20 . Laschuk et al explored the cobalt(II), osmium(II), iron(II) trimetal complexes of terpyridine ligand through ligand conjugation, thereby constructing an electrochromic energy storage devices 21 …”

Electrochromism or Water Splitting in Neutral Aqueous Solutions by a Metallo‐Organic Assembly

“…[25][26][27] We have developed in our laboratory a series of nanoscale metallo-organic assemblies (MAs) that are redox-active, thermally stable, and highly porous. [28][29][30][31][32][33][34][35][36][37][38][39] Coordination-based networks, comprising layers of polypyridyl complexes, and metals salts, have been generated on transparent conductive oxides (TCOs) by layerby-layer (LBL) dip-coating, automated spray-coating, or spin-coating. [29][30][31] While the polypyridyl complexes are the functional components, the metals salts (mainly palladium) function as a crosslinker by binding to the pyridyl moieties of polypyridyl complexes, generating 3D networks.…”

“…The large structural versatility of our MAs has resulted in diverse and potentially useful functions: interlayers for efficient inverted bulk-heterojunction solar cells, mimicry of logic gates and circuits (including flip-flops), memory elements, supercapacitors, anti-bacterial coatings, and directional electron transfer. [32][33][34][35][36][37] Furthermore, these materials have excellent charge trapping and multistate electrochromic characteristics. [38,39] Higuchi, Li, Kurth, Nishihara, Zenkina, Zharnikov, and others have studied related materials and demonstrated some of these functionalities.…”