The development of high-energy 5 V-class LiNi_0.5Mn_1.5O₄ batteries is severely limited by the instability of the cathode electrolyte interphase (CEI) at high temperature. Herein, we propose a nonflammable sulfone (SL)-based fluorinated hybrid electrolyte to form stable, uniform, and thin CEI layers, enabling Li||LiNi_0.5Mn_1.5O₄ batteries to achieve elevated electrochemical performance at 60 °C. The formed highly stable inorganic-dominated CEI, comprising Li_xSO_y, Li_xBO_y, and LiF inorganic compositions, exhibits good thermal stability and mechanical strength. Moreover, the robust CEI layer effectively shields the LNMO particles from undesirable side-reactions and stabilizes the interface within the LiNi_0.5Mn_1.5O₄ cathode during high-temperature cycling. In contrast to the conventional electrolyte, the Li||LiNi_0.5Mn_1.5O₄ battery employing a nonflammable SL-based electrolyte exhibits a stable capacity retention of 88.5% after 100 cycles at 60 °C free from the risk of thermal runaway. This study reveals valuable insights into advanced electrolyte technology, paving the way for safer applications of Co-free high-energy batteries in the future.

中文翻译：

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不易燃的砜基电解质，具有机械和热稳定的界面，使 LiNi0.5Mn1.5O4 能够在高温下工作


高能 5 V 级 LiNi_0.5Mn_1.5O₄ 电池的开发受到高温下阴极电解质界面 （CEI） 不稳定性的严重限制。在此，我们提出了一种基于不易燃砜 （SL） 的氟化混合电解质，以形成稳定、均匀和薄的 CEI 层，使 Li||LiNi_0.5Mn_1.5O₄ 电池在 60 °C 下实现更高的电化学性能。 形成的高度稳定的无机主导的 CEI，包括 Li_xSO_y、Li_xBO_y 和 LiF 无机组成，表现出良好的热稳定性和机械强度。此外，坚固的 CEI 层有效地保护 LNMO 颗粒免受不良副反应的影响，并在高温循环期间稳定 LiNi_0.5Mn_1.5O₄ 阴极内的界面。与传统电解质相比，Li||采用不易燃 SL 基电解质的 LiNi_0.5Mn_1.5O₄ 电池在 60 °C 下循环 100 次后表现出 88.5% 的稳定容量保持率，并且没有热失控的风险。这项研究揭示了对先进电解质技术的宝贵见解，为未来更安全的无钴高能电池应用铺平了道路。