甲氧基聚乙二醇丙烯酸酯在全固态电池中的应用

Application of poly(ethylene glycol)methyl ether acrylate in all-solid-state batteries

固态聚合物电解质作为全固态聚合物锂离子电池的核心材料,目前面临的主要难点是电导率低、电化学稳定性差等题。基于聚合物电解质的锂离子传输机理,采用甲氧基聚乙二醇丙烯酸酯和聚氧化乙烯制备出多支链固态聚合物电解质(PMEA@SSE),并以聚氧化乙烯固态电解质(PEO@SSE)作为对比样,对PMEA@SSE进行了傅里叶变换红外光谱仪(FT-IR)、电化学阻抗谱(EIS)、线性扫描伏安法(LSV)、扫描电子显微镜(SEM)、X射线能谱(EDS)、X射线衍射(XRD)以及全固态电池循环等测试和分析。结果表明,与PEO@SSE相比,PMEA@SSE具有更高的离子电导率(0.13 mS/cm vs.0.018 mS/cm,测试温度30℃),更宽的电化学窗口(4.2 V vs.3.8 V),以及更好的全固态电池循环稳定性(77次vs.31次循环,80%容量保持率,60℃下测试,0.1 C倍率,3.0~4.2 V电压范围)。本工作表明,甲氧基聚乙二醇丙烯酸酯部分替代聚氧化乙烯是一种改进聚氧化乙烯这一经典固态聚合物电解质材料的可行策略,将为后续固态聚合物电解质新材料的开发提供有益参考。

Solid polymer electrolyte is one of the critical materials in all solid polymer lithium-ion batteries.The main challenge for solid polymer electrolytes is their low conductivity and poor electrochemical stability.In this study,a novel solid polymer electrolyte named(PMEA@SSE)was prepared by combining poly(ethylene glycol)methyl ether acrylate(PMEA)with polyethylene oxide(PEO),based on the Li^(+)-conducting mechanism of polymer electrolyte.PEO electrolyte(PEO@SSE)was prepared as the control sample.The PMEA@SSE was evaluated by Fourier transform infrared spectrometer,electrochemical impedance spectroscopy,linear sweep voltammetry,scanning electron microscope,energy dispersive spectrometer,X-ray diffraction,and cell testing.The results revealed that the electrochemical stability window of PMEA@SSE was similarly higher than that of PEO@SSE(4.2 V vs.3.8 V)and that the ion conductivity of PMEA@SSE was higher than that of PEO@SSE(0.13 m S/cm vs 0.018 m S/cm,tested at 30℃).Furthermore,the solid-state battery prepared using PMEA@SSE exhibited better cycle performance than PEO@SSE(77 vs.31 cycles with a capacity retention of 80%).This work demonstrates that partially replacing PEO with PMEA is a feasible strategy for advancing the classical PEO solid electrolyte for application in all solid lithium batteries and provides new insights for further developing solid polymer electrolytes.