Solution-Processable Redox-Active Polymers of Intrinsic Microporosity for Electrochemical Energy Storage

Abstract

Redox-active organic materials have emerged as promising alternatives to conventional inorganic electrode materials in electrochemical devices for energy storage. However, the deployment of redox-active organic materials in practical lithium-ion battery devices is hindered by their undesired solubility in electrolyte solvents, sluggish charge transfer and mass transport, as well as processing complexity. Here, we report a new molecular engineering approach to prepare redox-active polymers of intrinsic microporosity (PIMs) that possess an open network of subnanometer pores and abundant accessible carbonyl-based redox sites for fast lithium-ion transport and storage. Redox-active PIMs can be solution-processed into thin films and polymer− carbon composites with a homogeneously dispersed microstructure while remaining insoluble in electrolyte solvents. Solutionprocessed redox-active PIM electrodes demonstrate improved cycling performance in lithium-ion batteries with no apparent capacity decay. Redox-active PIMs with combined properties of intrinsic microporosity, reversible redox activity, and solution processability may have broad utility in a variety of electrochemical devices for energy storage, sensors, and electronic applications.

Alkynyl Boosted High‐Performance Lithium Storage and Mechanism in Covalent Phenanthroline Framework

“…Sequentially, lithium atoms were then placed at different active sites of Alkynyl-CPF and the optimized geometries (Figure 5c) were obtained by simulations. [29] Combined with Figure 5a, it can be clearly observed that the site near C=N units of phenanthroline exhibits the most negative state and accepts 6 Li atoms (ΔE ad = À 0.43 eV) for each unit, indicating its strongest affinity for cations (such as Li + ) due to its higher electronegativity of N than C atoms. Then, the active sites of C�C bonds show a much negative value through the whole conjugated structure.…”

Porous Organic Polymer with Hierarchical Structure and Limited Volume Expansion for Ultrafast and Highly Durable Sodium Storage

“…To further explore the porosity of CPTA, the CO 2 (Figure 2h) adsorption–desorption method was applied as well. [ 42 ] As for CPTA, the CO 2 adsorption–desorption plots give a higher SSA of 130 m 2 g −1 with an average pore size of ≈0.5 nm (the inset in Figure 2h), indicating the domination of the micro‐pore structure in CPTA. The trimodal pores (i.e., macro‐/meso‐/micro‐) co‐existing in CPTA are favorable for exposing more electroactive sites, [ 43 ] boosting the ions/electrolyte transfer, and accommodating the volume expansion during cycling, [ 44–46 ] which can effectively enhance the Na‐storage capacity, cycling stability, and electrochemical kinetics for SIBs.…”

Templated Synthesis of 2D Polyimide Covalent Organic Framework for Rechargeable Sodium‐Ion Batteries

“…[21][22][23] The linker exchange approach is an effective approach for transforming amorphous covalent organic polymers (COPs) into highly crystalline COFs; therefore, can aid in accessing optimized materials for electrochemical energy storage. [24][25][26][27][28][29] Extending this approach to porous polyimides Scheme 1. Conventional synthetic route and the alternative linker exchange approach for a crystalline porous polyimide framework synthesis.…”

“…[ 21–23 ] The linker exchange approach is an effective approach for transforming amorphous covalent organic polymers (COPs) into highly crystalline COFs; therefore, can aid in accessing optimized materials for electrochemical energy storage. [ 24–29 ] Extending this approach to porous polyimides holds great promise, especially in advanced rechargeable lithium and sodium‐ion batteries wherein rapid ion and charge transfer and full accessibility of the redox‐active sites dictate device performance. [ 30–33 ] Such properties become even more crucial when sodium is employed because of its large ionic size and sluggish intercalation kinetics.…”