Tributyl borate (TBB) is studied as a protective additive that enhances the interfacial stability of a LiNi_0.5Mn_1.5O₄ cathode/electrolyte at 5 V and 55 °C. Upon addition of 0.5 vol % TBB to the electrolyte (1.0 M LiPF₆/EC:EMC:DMC, 1:1:1 wt %), the LiNi_0.5Mn_1.5O₄/Li cell maintains a discharge capacity of 99.4 mAh g^–1 at the 50th cycle at 55 °C, compared to that of the electrolyte without an additive, i.e., 36.6 mAh g^–1. Furthermore, the TBB-enhanced Li/LiNi_0.5Mn_1.5O₄ cell exhibits a higher discharge capacity of 96 mAh g^–1 at 3C, whereas the cell without TBB delivers only 84 mAh g^–1. Theoretical calculations and differential capacity (dQ/dV) versus voltage (V) analysis show that TBB improves the electrochemical performance at 5 V and 55 °C by preferentially oxidizing on the LiNi_0.5Mn_1.5O₄ surface. The results obtained from electrochemical impedance spectroscopy, scanning electron microscopy, transmission electron microscopy, X-ray photoelectron spectroscopy, X-ray diffraction, and inductively coupled plasma-mass spectroscopy measurements reveal that TBB generates a thin, less resistive film on the surface of LiNi_0.5Mn_1.5O₄. This TBB-derived film inhibits the decomposition of the carbonate solvent, while suppressing the dissolution of Ni and Mn ions from LiNi_0.5Mn_1.5O₄.

中文翻译：

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硼酸三丁酯对高温LiNi _0.5 Mn _1.5 O ₄阴极高温下电化学性能的影响

研究了硼酸三丁酯（TBB）作为保护性添加剂，该添加剂可增强LiNi _0.5 Mn _1.5 O ₄阴极/电解质在5 V和55°C下的界面稳定性。在电解液中添加0.5 vol％的TBB（1.0 M LiPF ₆ / EC：EMC：DMC，1：1：1 wt％）时，LiNi _0.5 Mn _1.5 O ₄ / Li电池可维持99.4 mAh g的放电容量^{– 1}在55℃下的第50次循环，相比于电解质的不具有添加剂，即，36.6毫安克^-1。此外，TBB增强的Li / LiNi _0.5 Mn _1.5 O ₄电池具有96 mAh g的更高放电容量在3C时为^–1，而没有TBB的电池仅提供84 mAh g ^–1。理论计算和微分容量（d Q / d V）与电压（V）分析表明，TBB通过在LiNi _0.5 Mn _1.5 O ₄表面上优先氧化来改善5 V和55°C时的电化学性能。从电化学阻抗谱，扫描电子显微镜，透射电子显微镜，X射线光电子能谱，X射线衍射和电感耦合等离子体质谱法获得的结果表明，TBB在LiNi的表面上产生了一层薄而电阻少的薄膜_0.5锰_1.5O ₄。该TBB衍生的膜抑制了碳酸酯溶剂的分解，同时抑制了Ni和Mn离子从LiNi _0.5 Mn _1.5 O _4中的溶解。