Machine Learning–Guided Solvation Engineering of Chiral Viologens for Durable Neutral Aqueous Organic Flow Batteries
Abstract
Abstract Conventional N ‐alkylated viologen electrolytes in neutral aqueous organic redox flow batteries (AORFBs) undergo irreversible nucleophilic S N 2 dealkylation degradation. Moreover, trial‐and‐error molecular design often fails to resolve the solubility–stability trade‐off in high‐concentration systems. Here we report a machine learning (ML) strategy using large language models (LLMs) trained on over 1300 AORFB studies to predict chiral viologens with ortho ‐dihydroxy motifs. This bonding network forms a dynamic, pH‐adaptive “solvation armor” that stabilizes the viologen structure. The R ‐/ S ‐ enantiomers (2.75/2.76 M) exhibit 1.66 times higher solubility versus RS ‐ racemate. Molecular simulations and in situ spectroscopy confirm that the dihydroxy groups protect reactive C─N bonds via a solvation structure (unrelated to chiral effect), enhancing stability to pH 11. The 1 M R 2+ / R +• redox couple sets a new record by achieving 99.42% capacity retention over 3652 cycles. The 1 M R ‐based AORFB shows 100% retention over 533 cycles, outperforming quaternary ammonium‐ ( [(NPr) 2 V]Cl 4 , 94.92%) and sulfonate‐modified viologen ( (SPr) 2 V) , 65.49%). Stable cycling across 0.1 ∼ 2.5 M demonstrates decoupling of degradation from concentration. This strategy is validated by 2.5 kg‐scale synthesis and Ah‐class stack testing (98.65% retention over 77 cycles), demonstrating industrial scalability. This work establishes a generalizable, ML‐enabled platform for electrolyte development, bridging molecular design and practical AORFB deployment.
Article Details
Authors (10)
Xu Liu
Haiyan Yu
State Key Laboratory of Tropical Oceanography, South China Sea Institute of Oceanology, Guangdong Provincial Key Laboratory of Applied Marine Biology, Chinese Academy of Sciences
Xiaotong Deng
Frontier Institute of Science and Technology Interdisciplinary Research Center of Frontier science and technology State Key Laboratory for Strength and Vibration of Mechanical Structures Institute of New Concept Sensors and Molecular Materials Shaanxi Key Laboratory of New Conceptual Sensors and Molecular Materials Engineering Research Center of Key Materials for Efficient Utilization of Clean Energy of Shaanxi Province National innovation Platform (Center) for Industry‐Education Integration of...
Jian‐Yue He
Frontier Institute of Science and Technology Interdisciplinary Research Center of Frontier science and technology State Key Laboratory for Strength and Vibration of Mechanical Structures Institute of New Concept Sensors and Molecular Materials Shaanxi Key Laboratory of New Conceptual Sensors and Molecular Materials Engineering Research Center of Key Materials for Efficient Utilization of Clean Energy of Shaanxi Province National innovation Platform (Center) for Industry‐Education Integration of...
Xuri Zhang
Frontier Institute of Science and Technology, Interdisciplinary Research Center of Frontier science and technology, State Key Laboratory for Strength and Vibration of Mechanical Structures, Engineering Research Center of Key Materials For Efficient Utilization of Clean Energy of Shaanxi Province, Xi'an Key Laboratory of Electronic Devices and Material Chemistry Xi'an Jiaotong University Xi'an Shaanxi P. R. China
Junjie Huang
Zengrong Wang
Frontier Institute of Science and Technology, Interdisciplinary Research Center of Frontier science and technology, State Key Laboratory for Strength and Vibration of Mechanical Structures, Engineering Research Center of Key Materials For Efficient Utilization of Clean Energy of Shaanxi Province, Xi'an Key Laboratory of Electronic Devices and Material Chemistry Xi'an Jiaotong University Xi'an Shaanxi P. R. China
Chenjing Liu
Frontier Institute of Science and Technology, Interdisciplinary Research Center of Frontier Science and Technology, State Key Laboratory for Strength and Vibration of Mechanical Structures, Institute of New Concept Sensors and Molecular Materials, Shaanxi Key Laboratory of New Conceptual Sensors and Molecular Materials, Engineering Research Center of Key Materials for Efficient Utilization of Clean Energy of Shaanxi Province, Xi’an Key Laboratory of Electronic Devices and Material Chemistry
Xin Zhang
Gang He