<p>The practical implementation of lithium metal batteries is hindered by unstable electrode-electrolyte interfaces and sluggish ion transport kinetics. Here, we report a molecular design strategy that remodels electrolyte solvation structures via the formation of hydrogen-bonded domains, thereby enhancing both the thermodynamics and interfacial dynamics of Li<sup>+</sup> transport. Specifically, we introduce 2-cyano-N-methylacetamide, an electrochemically stable hydrogen bond donor, as a cosolvent to construct stable nanoscale hydrogen-bonded domains ( &lt; 3.5 Å). 2-Cyano-N-methylacetamide generates both classical (H-bond, H<sup>δ⁺</sup>–O<sup>δ⁻</sup>) and nonclassical (Z-bond, N<sup>δ⁻</sup>–H<sup>δ⁺</sup>) hydrogen bonding, which disrupts loosely bound solvated clusters and induces tightly coordinated Li<sup>+</sup> solvation structures. The hydrogen-bonded domains facilitate the formation of oriented fast Li<sup>+</sup> transport channels. Accordingly, in Li | |LiNi<sub>0.8</sub>Co<sub>0.1</sub>Mn<sub>0.1</sub>O<sub>2</sub> cells cycled under demanding conditions of 4.7 V with a high areal capacity of ~3.0 mAh cm<sup>−2</sup>, the electrolyte enables a capacity retention of 78.8% after 400 cycles. In addition, a stable 4.7 V lithium metal pouch cell is demonstrated with a specific energy (based on the mass of all components) of 418.2 Wh kg<sup>−1</sup>. This work offers a useful electrolyte design principle on solvation chemistry and interfacial engineering for high-voltage lithium metal batteries.</p>

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Electrolyte chemistry of adaptive hydrogen bonded domains for high voltage lithium metal batteries

  • Zihao Yang,
  • Lingcai Zeng,
  • Zhengyu Ju,
  • Kaixiang Shi,
  • Jiajie Pan,
  • Ridong Hu,
  • Yuyang Wang,
  • Jianrong Zeng,
  • Yun Hong,
  • Quanbing Liu,
  • Guihua Yu

摘要

The practical implementation of lithium metal batteries is hindered by unstable electrode-electrolyte interfaces and sluggish ion transport kinetics. Here, we report a molecular design strategy that remodels electrolyte solvation structures via the formation of hydrogen-bonded domains, thereby enhancing both the thermodynamics and interfacial dynamics of Li+ transport. Specifically, we introduce 2-cyano-N-methylacetamide, an electrochemically stable hydrogen bond donor, as a cosolvent to construct stable nanoscale hydrogen-bonded domains ( < 3.5 Å). 2-Cyano-N-methylacetamide generates both classical (H-bond, Hδ⁺–Oδ⁻) and nonclassical (Z-bond, Nδ⁻–Hδ⁺) hydrogen bonding, which disrupts loosely bound solvated clusters and induces tightly coordinated Li+ solvation structures. The hydrogen-bonded domains facilitate the formation of oriented fast Li+ transport channels. Accordingly, in Li | |LiNi0.8Co0.1Mn0.1O2 cells cycled under demanding conditions of 4.7 V with a high areal capacity of ~3.0 mAh cm−2, the electrolyte enables a capacity retention of 78.8% after 400 cycles. In addition, a stable 4.7 V lithium metal pouch cell is demonstrated with a specific energy (based on the mass of all components) of 418.2 Wh kg−1. This work offers a useful electrolyte design principle on solvation chemistry and interfacial engineering for high-voltage lithium metal batteries.