Sun Zeyuan, Sun Mengting, Qin Siyu, Wang Meng, Zheng Yulong, Khau Brian, Li Han, Gartner Thomas E, Takacs Christopher J, Reichmanis Elsa
Department of Chemical and Biomolecular Engineering, Lehigh University, Bethlehem, PA, 18015, USA.
School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, GA, 30332, USA.
Adv Mater. 2025 Feb;37(8):e2414963. doi: 10.1002/adma.202414963. Epub 2024 Dec 4.
Organic mixed ionic-electronic conductors (OMIECs) have garnered significant attention due to their capacity to transport both ions and electrons, making them ideal for applications in energy storage, neuromorphics, and bioelectronics. However, charge compensation mechanisms during the polymer redox process remain poorly understood, and are often oversimplified as single-ion injection with little attention to counterion effects. To advance understanding and design strategies toward next-generation OMIEC systems, a series of p-channel carboxylated mixed conductors is investigated. Varying side-chain functionality, distinctive swelling character is uncovered during electrochemical doping/dedoping with model chao-/kosmotropic electrolytes. Carboxylic acid functionalized polymers demonstrate strong deswelling and mass reduction during doping, indicating cation expulsion, while ethoxycarbonyl counterparts exhibit prominent mass increase, pointing to an anion-driven doping mechanism. By employing operando grazing incidence X-ray fluorescence (GIXRF), it is revealed that the carboxyl functionalized polymer engages in robust cation interaction, whereas ester functionalization shifts the mechanism towards no cation involvement. It is demonstrated that cations are pivotal in mitigating swelling by counterbalancing anions, enabling efficient anion uptake without compromising performance. These findings underscore the transformative influence of functionality-driven factors and side-chain chemistry in governing ion dynamics and conduction, providing new frameworks for designing OMIECs with enhanced performance and reduced swelling.
有机混合离子-电子导体（OMIECs）因其能够同时传输离子和电子而备受关注，使其成为能量存储、神经形态学和生物电子学应用的理想选择。然而，聚合物氧化还原过程中的电荷补偿机制仍知之甚少，并且常常被过度简化为单离子注入，而很少关注抗衡离子效应。为了增进对下一代OMIEC系统的理解并推进设计策略，研究了一系列p型羧化混合导体。通过改变侧链功能，在用模型离液/促离子电解质进行电化学掺杂/去掺杂过程中发现了独特的溶胀特性。羧酸官能化聚合物在掺杂过程中表现出强烈的去溶胀和质量减轻，表明阳离子被排出，而乙氧羰基对应物则表现出显著的质量增加，表明存在阴离子驱动的掺杂机制。通过采用原位掠入射X射线荧光（GIXRF）技术，发现羧基官能化聚合物参与了强烈的阳离子相互作用，而酯官能化则使机制转向不涉及阳离子。结果表明，阳离子在通过平衡阴离子来减轻溶胀方面起着关键作用，能够在不影响性能的情况下实现有效的阴离子吸收。这些发现强调了功能驱动因素和侧链化学在控制离子动力学和传导方面的变革性影响，为设计具有更高性能和更低溶胀的OMIECs提供了新的框架。
