氟化锂及氮化亚铜人工固态电解质膜对锂离子电池正极三元材料的改性

在锂离子电池充放电过程中,电解液与电极材料发生反应,形成的固态电解质膜(solid electrolyte interphase,SEI)随着充放电次数的增加而变厚,这将降低电池的循环稳定性。所制备的人工固态电解质膜(a-SEI)可改善锂离子电池的循环稳定性,其主要成分为使用液相法制备的氟化锂(LiF)、氮化亚铜(Cu 3N)纳米颗粒。通过两种不同路径,将两种纳米颗粒先后在锂离子电池正极三元材料LiNi 0.8 Co 0.1 Mn 0.1 O 2(NCM811)电极片表面和活性材料颗粒表面涂覆生成一层a-SEI。使用扫描电子显微镜(SEM)、X射线衍射仪(XRD)、电化学阻抗谱(EIS)等材料表征和电化学分析方法,解析a-SEI对锂离子电池循环稳定性的影响。结果表明,NCM811材料表面包覆Cu 3N作为a-SEI的电化学性能最好,相比纯NCM811材料,50周循环后的容量保持率可提升26.5%。

Modification of Lithium Floride and Cuprous Nitride as Artificial Solid Electrolyte Interphase on Ternary Cathode Material of Lithium-Ion Batteries

During the charging and discharging process,the electrolyte can react with the electrode materials,and a layer of SEI(solid electrolyte interphase)formed thickens with the increase of the charging and discharging times,which will reduce the cycling stability of the battery.The phenomenon will greatly go against the cycling performance of lithium-ion batteries.Artificial-SEI layers were prepared to improve the cycling performance of batteries.LiF and Cu 3N nanoparticles were synthesized to form artificial-SEI layers on the surface of LiNi 0.8 Co 0.1 Mn 0.1 O 2(NCM811)electrodes and active material particles respectively through solution phase method.The effects of artificial-SEI on lithium-ion batteries were studied by scanning electron microscopy(SEM),X-ray diffraction(XRD),electrochemical impedance spectroscopy(EIS)and other materials characterization and electrochemical analysis methods.The results show that the Cu 3N artificial-SEI on active materials particles improves the capacity retention by 26.5%after 50 cycles.