Overview

• A team at Helmholtz‑Zentrum Berlin and the Technical University of Berlin created a radical‑cationic covalent organic framework, R‑TTF•+-COF, built from tetrathiafulvalene radical cations and trisulfide radical anions linked via benzothiazole.
• The [TTF]2•+ sites act as catalytic centers that bind lithium polysulfides and accelerate S–S bond cleavage and formation, curbing the shuttle effect inside the electrode.
• Lab lithium–sulfur cells using the material exceeded 1,500 cycles with roughly 0.027% capacity loss per cycle, outperforming prior COF hosts and typical sub‑1,000‑cycle benchmarks.
• Characterization combined solid‑state NMR and electron spin resonance with in situ X‑ray tomography at the BAMline at BESSY II, supported by theoretical calculations.
• The work appears in the Journal of the American Chemical Society (Aug. 19, 2025), and the authors emphasize the need for more stable radical building blocks and evaluation of manufacturing and real‑world deployment.