A modified self-extinguishing time (SET) device which enhances the reproducibility of the results is presented. Pentafluoro(phenoxy)cyclotriphosphazene (FPPN) is investigated as flame retardant electrolyte additive for lithium ion batteries (LIBs) in terms of thermal stability and electrochemical performance. SET measurements and adiabatic reaction calorimetry are applied to determine the flammability and the reactivity of a standard LIB electrolyte containing 5% FPPN. The results reveal that the additive-containing electrolyte is nonflammable for 10 s whereas the commercially available reference electrolyte inflames instantaneously after 1 s of ignition. The onset temperature of the safety enhanced electrolyte is delayed by ≈ 21 °C. Compatibility tests in half cells show that the electrolyte is reductively stable while the cyclic voltammogram indicates oxidative decomposition during the first cycle. Cycling experiments in full cells show improved cycling performance and rate capability, which can be attributed to cathode passivation during the first cycle. Post-mortem analysis of the electrolyte by gas chromatography-mass spectrometry confirms the presence of the additive in high amounts after 501 cycles which ensures enhanced safety of the electrolyte. The investigations present FPPN as stable electrolyte additive that improves the intrinsic safety of the electrolyte and its cycling performance at the same time.

中文翻译：

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五氟（苯氧基）环三磷腈作为阻燃剂添加剂的电化学性能评估和安全性研究，用于锂离子电池系统中，使用了一种新设计的可改善自熄性的装置

提出了一种改进的自熄时间（SET）装置，该装置可增强结果的可重复性。就热稳定性和电化学性能而言，研究了五氟（苯氧基）环三磷腈（FPPN）作为锂离子电池（LIB）的阻燃电解质添加剂。应用SET测量和绝热反应量热法确定含5％FPPN的标准LIB电解质的可燃性和反应性。结果表明，含添加剂的电解质在10 s内是不可燃的，而市售的参比电解质在点燃1 s后会立即燃烧。安全性增强的电解质的起始温度延迟了≈21°C。在半电池中进行的兼容性测试表明，电解质具有还原稳定性，而循环伏安图则表明在第一个循环中发生了氧化分解。全电池中的循环实验显示出改善的循环性能和倍率能力，这可以归因于第一循环中的阴极钝化。通过气相色谱-质谱法对电解质进行事后分析，确认了501个循环后大量添加剂的存在，从而确保了电解质的安全性。研究表明FPPN是稳定的电解质添加剂，可同时改善电解质的本质安全性和循环性能。这可以归因于第一个循环中的阴极钝化。通过气相色谱-质谱法对电解质进行事后分析，确认了501个循环后大量添加剂的存在，从而确保了电解质的安全性。研究表明FPPN是稳定的电解质添加剂，可同时改善电解质的本质安全性和循环性能。这可以归因于第一个循环中的阴极钝化。通过气相色谱-质谱法对电解质进行事后分析，确认了501个循环后大量添加剂的存在，从而确保了电解质的安全性。研究表明FPPN是稳定的电解质添加剂，可同时改善电解质的本质安全性和循环性能。