Huang Tao, Zheng Xiangzhen, Pan Ying, Li Qiaohong, Wu Maoxiang
ACS Appl Mater Interfaces. 2019 Jul 31;11(30):26872-26879. doi: 10.1021/acsami.9b07126. Epub 2019 Jul 16.
Tributyl borate (TBB) is studied as a protective additive that enhances the interfacial stability of a LiNiMnO cathode/electrolyte at 5 V and 55 °C. Upon addition of 0.5 vol % TBB to the electrolyte (1.0 M LiPF/EC:EMC:DMC, 1:1:1 wt %), the LiNiMnO/Li cell maintains a discharge capacity of 99.4 mAh g at the 50th cycle at 55 °C, compared to that of the electrolyte without an additive, i.e., 36.6 mAh g. Furthermore, the TBB-enhanced Li/LiNiMnO cell exhibits a higher discharge capacity of 96 mAh g at 3C, whereas the cell without TBB delivers only 84 mAh g. Theoretical calculations and differential capacity (d/d) versus voltage () analysis show that TBB improves the electrochemical performance at 5 V and 55 °C by preferentially oxidizing on the LiNiMnO 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 LiNiMnO. This TBB-derived film inhibits the decomposition of the carbonate solvent, while suppressing the dissolution of Ni and Mn ions from LiNiMnO.
硼酸三丁酯（TBB）作为一种保护添加剂进行了研究，它能增强LiNiMnO正极/电解质在5V和55℃下的界面稳定性。向电解质（1.0M LiPF/EC:EMC:DMC，1:1:1重量比）中添加0.5体积%的TBB后，LiNiMnO/Li电池在55℃下第50次循环时的放电容量为99.4mAh/g，而不含添加剂的电解质的电池放电容量为36.6mAh/g。此外，TBB增强的Li/LiNiMnO电池在3C倍率下的放电容量更高，为96mAh/g，而不含TBB的电池仅为84mAh/g。理论计算以及微分电容（dQ/dV）与电压（V）分析表明，TBB通过优先在LiNiMnO表面氧化来改善5V和55℃下的电化学性能。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测量获得的结果表明，TBB在LiNiMnO表面生成了一层薄的、电阻较小的膜。这种由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LiNiMnO中的溶解。
