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<p>Low-temperature operation remains a major challenge because sluggish Li<sup>+</sup> transport and aggravated polarization severely compromise energy delivery and cyclability. Here we develop a wide-temperature tri-salt electrolyte comprising LiBF<sub>4</sub>, LiFSI and LiDFOB in a PC/DME/iBA solvent matrix. With an optimized formulation (0.75&#xa0;M LiBF<sub>4</sub>, 0.2&#xa0;M LiFSI, 0.05&#xa0;M LiDFOB, PC : DME : iBA = 25:65:10, v/v/v, T-electrolyte), Li||LiCoO<sub>2</sub> batteries deliver high reversibility, strong rate capability and durable cycling from − 20 to 40&#xa0;°C. Remarkably, at −20&#xa0;°C, the optimized electrolyte sustains 143.5 mAh g<sup>− 1</sup> at 0.2&#xa0;C and preserves 129.7 mAh g<sup>− 1</sup> after 500 cycles, corresponding to ~ 85.5% of the room-temperature capacity, whereas a conventional low-temperature electrolyte rapidly decays to 47.2 mAh g<sup>− 1</sup> over the same cycles. Raman spectroscopy and molecular dynamics (MD) simulations reveal that anions and iBA participation reconstruct the Li<sup>+</sup> solvation sheath by suppressing PC over-coordination and lowering representative cluster binding energies, thereby reducing the desolvation penalty and promoting anion-derived inorganic-enriched interphases. XPS reveals that the T-electrolyte stabilizes both Solid Electrolyte Interphase (SEI) and Cathode Electrolyte Interphase (CEI) by promoting LiF/LiSO<sub><i>x</i></sub>F/borate-rich inorganic passivation while suppressing uncontrolled carbonate/ether decomposition, and by forming a self-limited cathode CEI in which ROCO<sub>2</sub>Li semicarbonates act as a compliant scaffold to preserve interfacial integrity under cycling at − 20&#xa0;°C. This work establishes a practical solvation-interphase design strategy for enhanced Li-storage at low temperature.</p>

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Anion-participating solvation in multi-salt cooperative electrolytes for enhanced low-temperature Li-storage capability

  • 期刊论文

  • 发表日期：

    2026年7月2日

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  • Bin Zhang,
  • Qing Yin,
  • Shouxun Peng,
  • Zeyu Zhao,
  • Meiyu Shi,
  • Xiwen Li,
  • Zheng Li,
  • Bin Xiao,
  • Xiuquan Gu,
  • Mingjia Zhi,
  • Eugene Chubenko,
  • Vitaly Bondarenko,
  • Hanna Bandarenka,
  • Yanwei Sui

摘要

Low-temperature operation remains a major challenge because sluggish Li+ transport and aggravated polarization severely compromise energy delivery and cyclability. Here we develop a wide-temperature tri-salt electrolyte comprising LiBF4, LiFSI and LiDFOB in a PC/DME/iBA solvent matrix. With an optimized formulation (0.75 M LiBF4, 0.2 M LiFSI, 0.05 M LiDFOB, PC : DME : iBA = 25:65:10, v/v/v, T-electrolyte), Li||LiCoO2 batteries deliver high reversibility, strong rate capability and durable cycling from − 20 to 40 °C. Remarkably, at −20 °C, the optimized electrolyte sustains 143.5 mAh g− 1 at 0.2 C and preserves 129.7 mAh g− 1 after 500 cycles, corresponding to ~ 85.5% of the room-temperature capacity, whereas a conventional low-temperature electrolyte rapidly decays to 47.2 mAh g− 1 over the same cycles. Raman spectroscopy and molecular dynamics (MD) simulations reveal that anions and iBA participation reconstruct the Li+ solvation sheath by suppressing PC over-coordination and lowering representative cluster binding energies, thereby reducing the desolvation penalty and promoting anion-derived inorganic-enriched interphases. XPS reveals that the T-electrolyte stabilizes both Solid Electrolyte Interphase (SEI) and Cathode Electrolyte Interphase (CEI) by promoting LiF/LiSOxF/borate-rich inorganic passivation while suppressing uncontrolled carbonate/ether decomposition, and by forming a self-limited cathode CEI in which ROCO2Li semicarbonates act as a compliant scaffold to preserve interfacial integrity under cycling at − 20 °C. This work establishes a practical solvation-interphase design strategy for enhanced Li-storage at low temperature.