Hubei Ruiyuan Electronic Co.,Ltd.
Major Breakthrough in Polymer Energy Storage Materials by Professor Xiaojie Lou's Team at Xi'an Jiaotong University
Release time：
2025-10-24
Polymer film capacitors are widely used in new energy vehicles and pulse power systems due to their ultrahigh power density and rapid charge/discharge capabilities.However, materials commonly used for such capacitors, like commercial biaxially oriented polypropylene (BOPP), face bottlenecks of low permittivity (εᵣ ~2.2) and weak breakdown strength (BDS ~600 MV/m).Although aromatic polymers (e.g., polyimide, polycarbonate) exhibit high insulation, their strong π-π stacking interactions induce a sharp increase in conductive loss under high electric fields, severely limiting improvements in energy storage density.Thus, developing polymer dielectric materials that simultaneously possess high energy storage density, high charge-discharge efficiency, and excellent stability remains a major challenge in the field of polymer capacitive energy storage.
Addressing this challenge, Professor Xiaojie Lou's team proposed a novel steric hindrance modulation strategy. By copolymerizing adamantane-functionalized norbornene (NBAd) with aromatic side-chain norbornene (PNB2APS) and combining molecular dynamics simulations, they designed the P(NB2APS-co-NBAd₀.₀₅) material.This study pioneers the application of a steric hindrance suppression mechanism to enhance breakdown strength in this field: adamantane groups expand the aromatic side-chain spacing from 6.8 Å to 7.4 Å, weaken π-π stacking interactions, and increase the free volume fraction, thereby elevating the breakdown strength (BDS) to 865 MV/m—a 42% improvement over the base material.The material also demonstrates outstanding energy storage performance: achieving a discharged energy density (Ud) of 23.5 J/cm³ under an ultrahigh electric field of 1000 MV/m, which is 412% that of BOPP; while maintaining Ud at 15 J/cm³ with an energy storage efficiency (η) exceeding 90% at 800 MV/m.Furthermore, the material exhibits exceptional stability: after 100,000 charge-discharge cycles, both Ud and η show no degradation. It also possesses self-healing breakdown capability—by maintaining the (C+N+S)/(O+H) ratio at a low 1.07 through molecular design, the carbonized zone becomes automatically isolated from electrodes after breakdown.This research not only provides a novel approach for the structural design of high-performance capacitive energy storage polymer materials, but also injects strong momentum into the field's future development.
Fig. a) Schematic of the design strategy. b) Maximum Ud vs. BDS comparison of P(NB2APS-co-NBAd₀.₀₅) with other recently synthesized polymers. c) Discharged energy density and efficiency of BOPP and P(NB2APS-co-NBAd₀.₀₅) tested at 200 MV/m over cycle number.
These research findings have been published in the internationally renowned journal Advanced Functional Materials under the title "Ultra-high Capacitance Energy Storage Enabled by Weakening the π-π Stacking Effect in Novel Polynorbornene".The Frontier Institute of Science and Technology at Xi'an Jiaotong University is the primary affiliation. Ph.D. candidate Bin Zhang is the first author, and Professor Xiaojie Lou is the corresponding author.
This research was supported by the National Natural Science Foundation of China, the Ordos Major Science and Technology Cooperation Project, and the Xi'an Jiaotong University Analytical and Testing Center.
Citation: China Electronic Components Association.
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