Host‐guest interactions are an attractive approach to design redox electrolytes, enabling to precisely tune the key properties for redox flow batteries such as half‐cell redox potential, solubility, and stability. Herein we report a host‐guest complex of highly water soluble (2‐hydroxypropyl)‐β‐cyclodextrin with 1‐decyl‐1′‐ethyl‐4,4′‐bipyridinium dibromide as anolyte in a new aqueous organic redox flow battery (AORFB). The supramolecular anolyte ensured the total RFB voltage increase of ≈9 % up to 0.97 V and provided a stable capacity delivery for more than 500 cycles with a capacity fade rate of 0.037 %/cycle (2.84 %/day) at high Coulombic (>99.5 %) and energy (>62 %) efficiencies. The results highlight host‐guest interactions as promising strategy towards more effective storage of renewable energy within AORFBs.

The possibility of designing a solvent/reagent for Wittig reactions from basic phosphonium salts is explored theoretically. In the suggested R 4 P + PhO – and Ph 3 PR + PhO – ionic liquids (ILs), the phenolate anion is prone to remove the α-proton from the alkyl chains, forming a phosphorous ylide. Significant hydrogen bonding between the oxygen atoms of the anions and α-hydrogen atoms of the cations were found by molecular dynamics simulations of these substances; therefore, proton transfer between the two ions is inherently supported by the structure of the liquid as well. The subsequent steps of the Wittig reaction from the phosphorous ylide were also found to be energetically possible. The mesoscopic structure of these materials exhibits a significant segregation into polar and nonpolar domains, which may also allow an easy dissolution of the substrates. The formation of a pentacoordinated phosphorous derivative through P–O bond formation was found to be also possible in the gas phase for both kind of compounds. Accordingly, having such basic anions in phosphonium-based ILs may produce such a neutral and therefore volatile species, which may hold further significant applications for these solvents in ion-exchange and separation techniques and in synthesis.

Along with a primary modification of redox active materials, an additional introduction of secondary noncovalent interactions can synergistically enhance bulk properties of electrolytes for redox flow batteries. Herein, we highlight the host–guest complex formation between tailored viologens and highly water soluble (2-hydroxypropyl)-β-cyclodextrin as a key electrolyte interaction to modulate relevant electrochemical properties of aqueous redox flow batteries (AORFBs). The cyclodextrin-modified AORFB anolytes demonstrated a complex interrelation of molecular structure and inherent binding activity as well as bulk electrochemical stability of the anolyte. The screening of different combinations of viologen substituents in the presence of cyclodextrin enabled an electrochemically stable AORFB performance for more than 500 cycles with a temporary capacity fade rate of 0.26%/day at high energy (>70%) and Coulombic (>99.7%) efficiencies. A selective interplay of supporting electrolytes and engineered redox active materials is a promising strategy for enhanced energy characteristics of AORFB electrolytes.

The design of responsive coatings has gained increasing attention recently, with light-responsive interfaces receiving particular appreciation, as their surface properties can be modulated with excellent spatiotemporal control. In this article, we present light-responsive conductive coatings acquired through a copper(I)-catalyzed azide–alkyne cycloaddition (CuAAC) reaction between electropolymerized azide-functionalized poly(3,4-ethylenedioxythiophene) (PEDOT-N 3 ) and arylazopyrazole (AAP)-bearing alkynes. The UV/vis and X-ray photoelectron spectroscopy (XPS) data indicate a successful post-modification, supporting a covalent attachment of AAP moieties to PEDOT-N 3 . The thickness and degree of PEDOT-N 3 modification are accessible by varying the amount of passed charge during electropolymerization and time of reaction, respectively, providing a degree of synthetic control over the physicochemical material properties. The produced substrates demonstrate a reversible and stable light-driven switching of photochromic properties in both “dry” and swelled states, as well as efficient electrocatalytic Z → E switching. The AAP-modified polymer substrates exhibit a light-controlled wetting behavior, demonstrating a consistently reversible switching of the static water contact angle with a difference up to 10.0° for CF 3 -AAP@PEDOT-N 3 . The results highlight the application of conducting PEDOT-N 3 for the covalent immobilization of molecular switches while preserving their stimuli-responsive features.

Light‐responsive surfaces are attracting increasing interest, not least because their physicochemical properties can be selectively and temporally controlled by a non‐invasive stimulus. Most existing immobilization strategies involve the chemical attachment of light‐responsive moieties to the surface, although this approach often suffers from a low surface concentration of active species or a high inhomogeneity of applied coatings. Herein we present electropolymerization of carbazoles as a facile and rapid approach for preparing light‐responsive azo‐based surface coatings. The electrochemical oxidative polymerization of bis‐carbazole containing azo‑monomers yields stable films in which the photochemical properties and specific pH sensitivity of azo molecular switches are retained. Moreover, the molecular design enables electrocatalytic control over Z → E azo double bond isomerization facilitated by the conductive polycarbazole backbone. Ultimately, the high degree of control over macromolecular properties yields conductive surface coatings responsive to a range of stimuli, showing great promise as a strategy for versatile application in organic electronics.