Mixed Ionic-Electronic Transport Properties in n-Type Conducting Polymers and Their Applications

Conducting polymers (CPs) with high electronic conductivity and solution-processability have gained great attention since the pioneering work on doped polyacetylene. The doping process, crucial for preparing conducting polymers, typically introduces additional counter-ions when increasing the material’s carrier concentration, resulting in a mixed ion-electron transport. To address the challenges associated with low doping efficiency and conductivity in n-type conducting polymers, we developed a new construction method that combines oxidative polymerization with in situ n-doping. This approach led to the creation of a solution-processed n-type conducting polymer poly(benzodifurandione) (PBFDO) with ultrahigh conductivity (>2000 S/cm), offering new possibilities for printed electrodes and organic circuits.^{[1, 2]} Notably, these materials exhibit high doping efficiency and ion transport capacity. Leveraging these properties, high-performance n-type organic electrochemical transistors (OECTs) with impressive μC* values (＞400 F cm−1 V−1 s−1) and corresponding integrated circuits were achieved.^{[3, 4]} Subsequently, to further solve the challenges of non-impregnation of the PBFDO film with the electrolyte solution, varying amounts of polyethylene glycol (PEG) side chains were incorporated into highly conductive PBFDO system, enabling the development of customizable n-type OECTs with enhanced ion transport capabilities.^[5] Recent advancements in harnessing the high electronic conductivity of PBFDO, alongside its synergistic cation transport properties (e.g., lithium ions), culminated in the successful development of practical lithium-organic batteries with a capacity of over 2.5 Ah. The crystalline conducting polymer-based cathode exhibits an impressive electrical conductivity of 1400 S cm-1 and a Li+ diffusion coefficient of approximately 10-8 cm2 s-1. Remarkably, our organic pouch cells can stably operate over a wide temperature range of −60 to 80 °C, surpassing all reported inorganic-based lithium batteries in this regard. These significant achievements underscore the promise of n-type conducting polymers with mixed ionic-electronic transport capabilities in advancing organic electronic devices.


Reference
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