For decades, researchers have sought efficient ways to overcome the sluggish sulfur redox reactions that limit the practical application of lithium–sulfur batteries. Although various electrocatalysts have been developed to accelerate sulfur redox reactions, improving catalytic performance without sacrificing stability remains a major challenge. Recently, the chiral-induced spin selectivity (CISS) effect has emerged as a promising strategy for regulating electron spin during electrochemical reactions. However, whether the strength of chirality can be deliberately tuned to optimize catalytic performance has remained largely unexplored.
Now, writing in National Science Review , researchers led by Prof. Hongsen Li at Qingdao University report that precisely tuning the chiral asymmetry factor of chiral catalysts provides an effective way to manipulate the spin state of catalytic sites, thereby accelerating sulfur redox reactions and significantly improving the electrochemical performance of lithium–sulfur batteries.
The CISS effect enables chiral materials to preferentially transport electrons with one spin orientation, producing spin-polarized charge carriers without the need for an external magnetic field. Previous studies have demonstrated that spin polarization can influence catalytic reactions involving spin-sensitive intermediates. Yet an important question remained unanswered: can enhancing the degree of chirality further enhance spin polarization and, consequently, improve catalytic performance?
To answer this question, the research team synthesized cobalt oxide nanoparticles modified with chiral molecules and systematically regulated their asymmetry factor through an external magnetic field. Circular dichroism spectroscopy confirmed that the magnetic field progressively increased the asymmetry factor while preserving the crystal structure and morphology of the catalysts. The researchers then combined electrochemical measurements with theoretical calculations to examine how these changes influenced sulfur redox reactions.
The results revealed a clear correlation between the asymmetry factor and catalytic performance. As the asymmetry factor increased, the catalysts exhibited faster charge transfer, accelerated sulfur redox reaction kinetics, and more efficient lithium sulfide nucleation and decomposition. Batteries employing the optimized chiral catalyst delivered higher capacities, superior rate capability, and remarkable long-term cycling stability compared with both non-chiral catalysts and untreated counterparts.
To uncover the underlying mechanism, the team performed density functional theory calculations together with spectroscopic characterization. Their analyses showed that increasing the asymmetry factor progressively enhanced the spin state of cobalt catalytic sites. This spin-state regulation shifted the electronic structure of the catalyst, strengthened orbital interactions between cobalt 3d states and sulfur 3p orbitals, and lowered the energy barriers for sulfur redox reactions. Rather than merely improving the adsorption of lithium polysulfides, the enhanced spin polarization fundamentally accelerated the reaction kinetics throughout the sulfur redox process.
The study also demonstrates that catalytic performance can be continuously tuned by regulating the magnitude of the asymmetry factor, establishing a quantitative relationship between chirality, spin polarization, and electrochemical activity. This finding provides experimental evidence that catalytic performance is determined not simply by the presence of chirality, but by the degree of chirality.
“We were inspired by a simple idea: the best solutions are often the simplest ones. So we asked ourselves whether it would be possible to improve catalytic performance without changing the catalyst itself. We found that regulating the chiral asymmetry factor enables precise control over the spin state of catalytic sites, leading to accelerated sulfur redox reactions and enhanced electrochemical performance of lithium–sulfur batteries. We hope our findings will encourage researchers to further explore the role of chirality in electrocatalysis and provide new insights into designing catalysts through spin-state regulation,” said Prof. Hongsen Li.
The researchers believe that the work extends the application of the CISS effect beyond spintronics and molecular electronics into electrochemical energy storage. By introducing spin-selective catalysis as a controllable design principle, the study offers a new strategy for developing high-performance electrocatalysts not only for lithium–sulfur batteries but also for a broad range of electrochemical energy-conversion technologies. Future studies may explore how chiral engineering can be combined with catalyst composition and structural design to further enhance spin-dependent catalytic processes and enable next-generation energy storage systems
National Science Review
Experimental study