UCLA

Long cycle life and high energy/power density are imperative to electrochemical energy storage systems. Conducting polymers like polyaniline have shown great potential as electroactive electrode materials but are limited by poor cycling and rate performance. To address these challenges, we have developed molecular engineering approaches to construct advanced conducting polymer hybrid materials for high-performance supercapacitors. One approach is enabled by the formation of covalent linkages between a 3D graphene network and short-chain conducting polymers built through azide click chemistry. An ultralong cycle life can be achieved by the designed electrode material while the capacitance can be further boosted using a redox-active electrolyte. We further seek to develop a scalable, effortless, and cost-efficient approach toward the fabrication of conducting polymer-based electrodes to reduce the time/energy consumption associated with conventional high-temperature synthetic methods. A simple one-step laser-induced stabilization of aniline oligomers on carbon nanotubes is established through amide covalent coupling. By taking advantage of the short-chain conducting polymers and the covalent connections, the designed electrode exhibits remarkable cycling stability and good rate capability. To further understand the capacitance degradation mechanisms of aniline oligomer-based materials during long-term cycling, two composite electrodes based on aniline trimers and carbon nanotubes are studied as model systems and are systematically investigated at both pre-cycling and post-cycling states through physicochemical and electrochemical characterizations. Furthermore, a promising nanocomposite based on an interpenetrating network of polyaniline and lignosulfonate has been designed as a waste-to-wealth approach to improve the supercapacitive performance of polyaniline. Additionally, a facile and green electrosynthesis approach is presented to fabricate a polydopamine nanofilm supported on oxygen-functionalized carbon cloth, which delivers high energy density and outstanding cycling stability. These studies present effective molecular design and facile fabrication approaches toward next-generation flexible, robust, and sustainable energy storage devices.