Synthesis of anthraquinone based electroactive polymers: A critical review

Conducting polymers or synthetic monomers have revolutionized the world and are at the heart of scientific research having a scope of vast diverse applications in many technological fields. The conducting and redox polymers have been investigated as energy storage systems because of their better sustainability, ease of synthesis, and environmental compatibility. Owing to the conducting properties of quinones, they gain too much importance among the researchers. Keeping in view the importance and sustainability of conducting polymers, for the first time, this study compiles a detailed overview of synthetic approaches followed by investigations on electrochemical properties and future directions. This study critically examines the synthetic process of simple monomers, substituted monomers, and polymers of anthraquinone (AQ) under the classification of low- and high-molecular-weight AQ–based derivatives, their working principles, and their electrochemical applications, which enable us to explore their novel possible application in automotive, solar cell devices, aircraft aileron, and biomedical equipment. Irrefutably, we confirm that high-molecular-weight polymeric AQ compounds are best in comparison with low-molecular-weight AQ monomers because they have pre-eminent properties over monomeric systems. Because of the significant properties of AQ, polymeric systems are high demanding and have emerged as a hot topic among the researchers these days. In the current scenario, this study is of immense importance because it identifies and discusses the right and sustainable combination and paves the way to utilize these novel materials in different technologies

Manipulation of Disodium Rhodizonate: Factors for Fast-Charge and Fast-Discharge Sodium-Ion Batteries with Long-Term Cyclability

Organic sodium‐ion batteries (SIBs) are one of the most promising alternatives of current commercial inorganic lithium‐ion batteries (LIBs) especially in the foreseeable large‐scale flexible and wearable electronics. However, only a few reports are involving organic SIBs so far. To achieve fast‐charge and fast‐discharge performance and the long‐term cycling suitable for practical applications, is still challenging. Here, important factors for high performance SIBs especially with high capacity and long‐term cyclability under fast‐charge and fast‐discharge process are investigated. It is found that controlling the solubility through molecular design and determination of the electrochemical window is essential to eliminate dissolution of the electrode material, resulting in improved cyclability. The results show that poly(vinylidenedifluoride) will decompose during the charge/discharge process, indicating the significance of the binder for achieving high cyclability. Beside of these, it is also shown that decent charge transport and ionic diffusion are beneficial to the fast‐charge and fast‐discharge batteries. For instance, the flake morphology facilitates the ionic diffusion and thereby can lead to a capacitive effect that is favorable to fast charge and fast discharge

Organic batteries

Polymers bearing redox-active groups can be successfully utilized as active electrode material in organic batteries. The resulting battery materials can compete with inorganic battery materials, in particular in terms of theoretical capacity, power and energy density. Moreover, beneficial features of organic compounds like lightweight, flexibility, and printability make them promising candidates as active electrode materials for the next generation of secondary batteries. The richness of the organic chemistry provides a large variety of redox-active structures that can be utilized as active material in organic batteries. In particular quinones and their derivates are very promising candidates because of their tunable redox potential involving two electrons accompanied with low molar mass and high electrochemical stability. However, the synthesis of polymers bearing quinone units revealed to be challenging, because of the polarity of the carbonyl moiety and the radical scavenging properties of the quinone structure, which exclude common polymerization techniques. The introduction of methyl-groups to the benzoquinone core reduces the radical scavenging properties and enables radical polymerization of the methacrylate monomer. Nevertheless, the second electrochemical reduction of these polymers is irreversible possibly due to the nucleophilic attack of the formed anion to the ester functionality, which makes them not suitable as active material in batteries. Another possibility to apply the free radical polymerization technique is the introduction of a vinyl group to an aromatic substituent of the benzoquinone core. The direct conjugation inhibits the radical quenching abilities and further stabilizes the radical formed during the polymerization reaction. Thienyl substituents were introduced to the quinone core to lower the redox potential and a vinyl group was attached at position two in a four-step procedure. Polymers obtained from this monomer exhibit in lithium salt containing electrolytes a two-staged redox behavior displayed as one broad redox wave. Prototype lithium organic batteries with this material exhibit a capacity of 217 mAh/g at an average discharge cell potential of 2.2 V and a high rate performance with up to 10C without significant capacity decrease (complete charge or discharge within 6 min). However, the redox reaction is not side reaction-free and the capacity fades upon charge/discharge cycling

Low-Congestion Shortcuts for Graphs Excluding Dense Minors

We prove that any n-node graph G with diameter D admits shortcuts with congestion O(δD log n) and dilation O(δD), where δis the maximum edge-density of any minor of G. Our proof is simple and constructive with a tildeΘ (δD)-round1 distributed construction algorithm. Our results are tight up to logarithmic factors and generalize, simplify, unify, and strengthen several prior results. For example, for graphs excluding a fixed minor, i.e., graphs with constant δ, only a O (D2) bound was known based on a very technical proof that relies on the Robertson-Seymour Graph Structure Theorem. A direct consequence of our result is this: many graph families, including any minor-excluded ones, have near-optimal tildeΘ(D)-round distributed algorithms for many fundamental communication primitives and optimization problems in the standard synchronous message-passing model with logarithmic message sizes, i.e., the CONGEST model. These problems include minimum spanning tree, minimum cut approximation, and shortest-path approximations