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DOI number:10.1002/anie.6167442

Journal:Angewandte Chemie International Edition

Abstract:Sodium-based Prussian blue analogues (NaPBA) are promising cathodes for sodium-ion batteries owing to their high capacity and low cost. Nonetheless, rapid capacity fading during prolonged cycling remains a critical challenge, as the underlying degradation mechanisms are not fully understood. Here, we employ deuterium isotope labeling to unveil a dual-coupled degradation pathway in NaPBA cathodes, where crystalline water-induced lattice distortion is coupled with defect-triggered electrolyte decomposition. Density functional theory screening identifies In(OTf)3 as a multifunctional electrolyte additive, which suppresses both degradation processes via synergistic cation–anion effects. Molecular dynamics simulations and isotope-ratio mass spectrometry (IRMS) reveal that In3+ strongly coordinates with crystalline water, suppressing its repeated insertion/extraction and preventing framework collapse, while OTf-− anions passivate [Fe(CN)6]4− vacancies, reducing solvent adsorption and inhibiting electrolyte decomposition at defect sites. Consequently, the NaPBA||Na cells incorporating In(OTf)3 exhibit significantly improved electrochemical performance, demonstrating 80.63% capacity retention after 1000 cycles at 1C and nearly threefold higher discharge capacity at 20C compared to baseline cells, outperforming the most reported PBA-based batteries. This cation–anion modulation strategy provides a general design principle for electrolyte engineering in PBA-based energy-storage systems.

Indexed by:Journal paper

Translation or Not:no

Date of Publication:2026-07-13

Links to published journals:https://onlinelibrary.wiley.com/doi/abs/10.1002/anie.6167442