Chirality‑induced suppression of singlet oxygen in lithium–oxygen batteries with extended cycle life

Lithium–oxygen (Li–O₂) batteries hold transformative potential for next-generation energy storage due to their ultra-high theoretical energy density (~3.5 kWh kg^-1). However, their practical deployment is hindered by poor cycle life caused by singlet oxygen (¹O₂) generation, which triggers parasitic reactions and degrades cell components. Now, a multidisciplinary team led by Prof. Dong Ha Kim (Ewha Womans University) and Prof. Filipe Marques Mota (University of Lincoln) has introduced chiral cobalt oxide nanosheets (Co₃O₄ NSs) as cathode materials that suppress ¹O₂ formation through the chirality-induced spin selectivity (CISS) effect, unlocking unprecedented stability in Li–O₂ systems.

Why Singlet Oxygen Suppression Matters

• Cycle Life Bottleneck:
  ¹O₂ is a highly reactive species formed during charge/discharge, leading to electrolyte decomposition, electrode corrosion, and rapid capacity fade.
• CISS Effect as a Game-Changer:
  Chiral materials can filter electron spins, favoring triplet oxygen (³O₂) formation over ¹O₂, thereby minimizing side reactions and enhancing reversibility.
• Performance Leap:
  R-Co₃O₄/CP cathodes achieve 3.7× less ¹O₂ during discharge and 3.2× less during charge, translating to >300 hours of stable cycling vs. ~200 hours for achiral counterparts.

Innovative Design and Features

• Scalable Chiral Co₃O₄ Nanosheets:
  Electrodeposited using BINOL as a chirality inducer, forming binder-free, high-surface-area nanosheets on carbon paper with low Co loading (5 wt%).
• Spin-Polarized Charge Transport:
  Magnetic conductive AFM confirms 64.4% spin polarization in R-Co₃O₄, enabling spin-selective electron transfer that suppresses ¹O₂ generation.
• Operando Spectroscopic Validation:
  DEMS shows near-theoretical O₂ evolution (2.04 e⁻/O₂), while photoluminescence and UV–Vis with DMA probe confirm dramatic ¹O₂ suppression in real time.

Applications and Future Outlook

• Stable Li–O₂ Batteries:
  R-Co₃O₄/CP delivers lower charge overpotentials (~0.4–0.5 V reduction), higher round-trip efficiency, and 33+ stable cycles under fixed-capacity conditions.
• Mechanistic Insights:
  DFT reveals enhanced Co 3d–O 2p hybridization, lower ORR/OER overpotentials, and favorable Li₂O₂ surface growth, reducing reactive intermediates that trigger ¹O₂.
• Scalable and Sustainable:
  The electrodeposition-based synthesis is low-cost, substrate-agnostic, and compatible with roll-to-roll manufacturing, offering a practical pathway to commercialization.
• Beyond Li–O₂:
  This CISS-enabled strategy is extendable to Li–S, metal–air, and hybrid electrolysis systems, where oxygen radical management is critical.

This pioneering study establishes chiral electrocatalysis as a new design paradigm for controlling reactive oxygen species in energy storage. By merging spintronics with electrochemistry, it opens a new frontier in high-energy, long-life batteries essential for electric aviation, grid storage, and sustainable energy futures.

Stay tuned for more breakthroughs from Prof. Dong Ha Kim, Prof. Filipe Marques Mota, and their global collaborators!