Active Organic Salts Enabling Non-Intrusive Electrolyte Presodiation Strategy.

Journal: Advanced materials (Deerfield Beach, Fla.)
Published Date: May 6, 2025

Abstract

Na-ion batteries show great promise, but their practical utilization is hindered by irreversible Na-ion loss during cell formation, resulting in initial coulombic efficiencies typically below 80%. Conventional presodiation methods, which involve solid additives in the cathode, can compromise electrode integrity and leave deteriorated residues, especially with high Na ion compensation (20%). An electrolyte presodiation approach is introduced that utilizes sodium thiocyanate (NaSCN) as an electrolyte additive, discovered through cheminformatics and machine learning. This organic salt decomposes at 3.3-4.0 V, releasing active Na ions and forming a cosolvent without damaging the electrode and the cell, as confirmed by spectroscopic and microscopic analyses. The method improves the initial coulombic efficiency of a hard carbon|P2-NaNiMnTiO pouch cell from 80.8% to 95.2%, with a capacity retention of 84.5% over 400 cycles. These findings present a practical and non-intrusive way to address Na-ion deficiency challenges in Na-ion batteries.

Authors

  • Shu Chen
    Department of Materials, London Centre for Nanotechnology, Imperial College London SW3 UK.
  • Guanbin Wu
    State Key Laboratory of Molecular Engineering of Polymers, Department of Macromolecular Science, Institute of Fiber Materials and Devices, Collaborative Innovation Center of Chemistry for Energy Materials, Research Center of AI for Polymer Science, Fudan University, Shanghai, 200438, China.
  • Pai Wang
    State Key Laboratory of Molecular Engineering of Polymers, Department of Macromolecular Science, Institute of Fiber Materials and Devices, Collaborative Innovation Center of Chemistry for Energy Materials, Research Center of AI for Polymer Science, Fudan University, Shanghai, 200438, China.
  • Zilong Zheng
    Big Data Center, The Seventh Affiliated Hospital of Sun Yat-sen University, Shenzhen 518107, P.R. China.
  • Wenwen Wang
    Department of Computer Science, University of Georgia, Athens, GA, USA.
  • Yue Gao
    Institute of Medical Technology, Peking University Health Science Center, Beijing, China.

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