Through the design and assessment of five different polyimide structures, a groundbreaking study conducted by researchers from Jilin University and the Chinese Academy of Sciences was published in eScience in August 2024. It showed how adding carbonyl and conjugated structures can improve the performance of lithium-ion batteries and provided a roadmap for further developments.
Image Credit: eScience
Organic electrode materials are praised for their environmental friendliness and versatility, making them ideal options for next-generation energy storage devices. However, limitations such as low active-site density and inefficient use have hampered their practical use. Addressing these challenges necessitates a better knowledge of how molecule structure influences electrochemical performance—an area in which great progress is already being made.
The researchers created and evaluated five polyimides—PTN, PAN, PMN, PSN, and PBN—each with unique molecular changes to enhance performance. Carbonyl groups significantly enhanced active-site density, producing more redox-active sites and higher theoretical capacity. Increasing molecule stiffness was crucial for improving accessibility, minimizing excessive stacking, and maximizing electrochemical interactions.
Among the designs, PTN stood out for its large capacity (212 mAh g⁻¹ at 50 mA g⁻¹), stability, and rate performance. Conjugated arrangements between carbonyl groups increased active site reactivity, allowing for efficient charge transfer and stabilization of radical intermediates.
All polyimides demonstrated excellent cycling stability, with capacity retention rates surpassing 97% after extended usage. This highlights the strength of this molecular engineering method. These findings provide new possibilities for developing high-performance organic electrode materials.
This research highlights how strategic molecular design can fundamentally enhance electrochemical properties. By focusing on structure-function relationships, we have opened the door to more sustainable and efficient energy storage solutions that meet the demands of modern applications.
Hongyan Yao, Professor and Study Lead Researcher, Chinese Academy of Sciences
This finding has far-reaching ramifications for the future of lithium-ion battery technology. The improved polyimide cathodes are ideal for portable devices, electric cars, and large-scale energy grids. By overcoming critical constraints of organic cathodes, this study helps to accelerate the worldwide transition to cleaner and more efficient energy systems, paving the way for technologies that support a greener, more sustainable future.
The authors acknowledge the funding provided by the Science and Technology Development Plan of Jilin Province, P. R. China, and the National Natural Science Foundation of China.
Journal Reference:
Wang, J., et al. (2025) Towards high performance polyimide cathode materials for lithium–organic batteries by regulating active-site density, accessibility, and reactivity. eScience. doi.org/10.1016/j.esci.2023.100224