N‐Substituted Carbazole Derivate Salts as Stable Organic Electrodes for Anion Insertion

Abstract

Herein the design, synthesis and electrochemical characterization of a set of insoluble molecular carbazole derivatives for electrochemical energy storage is proposed. Two strategies, based on the incorporation of an insoluble fragment or dimerization, were carried out to avoid the dissolution of the active material in the organic carbonate‐based liquid electrolyte solvent. The synthesized compounds enable the reversible anion intercalation from electrolyte, around 4.0 V vs. Li, through a p‐type mechanism, and showed an improvement in cycling stability, making them suitable for application as metal‐free positive electrodes for electrochemical energy storage systems. A first investigation to determine the impact of the electrolyte composition on the anion insertion mechanism and complemented with understanding of the redox mechanism was also carried out.

Plastic Crystal Fast Ion‐Conductor Electrolyte Enabled Ultra‐Low Temperature Rechargeable Organic Battery

“…They do have voltage advantage over other organic electrode materials, however the intrinsic efficiency issue of Li 4 NTC and TA much increases the difficulty to identify an optimum N/P ratio and hence we observed a relatively lower capacity of the Li 4 NTC/TA full cell). [36][37][38] In Figure 3b, the PI5/PTPAn full-cell using 1 m EMPFSI MA electrolyte was tested under different current density (0.2 C-10 C) at −95 °C. 85% theoretical capacity was reserved at 0.2 C, even when the current rate increased to 10 C, still 59% capacity was preserved.…”

A bipolar-type covalent organic framework on carbon nanotubes with enhanced density of redox-active sites for high-performance lithium-ion batteries

“…Nevertheless, the low redox potential (o2.9 V vs. Li/Li + ) of these n-type organic electroactive groups, such as CQO, CQN, and imide groups, restricts the energy densities of the corresponding LIB cathodes based on COF materials. [36][37][38] Recent studies reveal that introducing p-type organic electroactive moieties, such as phenoxazine, 39 thianthrene, 40,41 and triazine, 42,43 or bipolartype organic electroactive moieties, 34 such as 2,2,6,6-tetramethylpiperidinooxy, into COFs can result in a high redox potential (43.0 V vs. Li/Li + ) since these moieties possess ''holes'' in the notion of electron deficiency. However, the high molecular mass and the small amount of redox-active moieties of the p-type and bipolar-type building units would result in low theoretical specific capacities.…”

Carbonyl-Based Redox-Active Compounds as Organic Electrodes for Batteries: Escape from Middle–High Redox Potentials and Further Improvement?

“…The quest for performant organic electrodes has thus given rise to different strategies, with the objective to develop suited materials or electrode manufacturing for this type of application (see, e.g. , refs − ). In this area, fancy ways of discovering new materials precisely targeted toward device optimization with departure from standards mainly rely on the conjunction of synthesis feasibility and subsequent obtention of satisfying features especially (but not solely) of electrochemical nature.…”