Poly(acrylic acid) (PAA) based binders have been widely used for the high capacity silicon anodes of lithium-ion batteries. While numerous promising progress has been reported, there is no general guideline for choosing the right PAA binders for optimized cycling performance. In this report, aiming to optimize the cycling performance of the Si/graphite composite anodes (15 wt% Si), we systemically investigated a series of PAA binders by validating their molecular weights (MWs) and correlating them to the cycling performance of the anodes fabricated with such binders. The gel permeation chromatography (GPC) was used to validate the MWs of six PAA binders (PAA1 to PAA6). Those binders then underwent a series of characterizations, including rheology study, half-cell cycling, scanning electron microscope (SEM), and Fourier-transform infrared spectroscopy (FTIR). It is observed that the MWs of PAA binders not only affected the viscosities of the binder solutions but also impacted the cycling performance, possibly due to the cohesion changes. A range of 24–150 kDa is found to be optimal for minimizing the rate and extent of capacity fade and maintaining the cohesion in the electrode matrix despite the dramatic volumetric changes due to Si alloying.

聚（丙烯酸）（PAA）基粘合剂已广泛用于锂离子电池的高容量硅阳极。尽管已报告了许多令人鼓舞的进展，但没有选择通用的准则来选择合适的PAA粘合剂以优化循环性能。在本报告中，旨在优化Si /石墨复合阳极（15 wt％Si）的循环性能，我们通过验证其分子量（MWs）并将其与阳极的循环性能相关联，系统地研究了一系列PAA粘合剂用这种粘合剂制成的。凝胶渗透色谱法（GPC）用于验证六种PAA粘合剂（PAA1至PAA6）的分子量。然后对这些粘合剂进行了一系列表征，包括流变学研究，半电池循环，扫描电子显微镜（SEM），和傅立叶变换红外光谱（FTIR）。观察到，PAA粘合剂的分子量不仅影响粘合剂溶液的粘度，而且还可能由于内聚力变化而影响循环性能。发现范围为24–150 kDa是最佳的，以最大程度地减小容量衰减的速率和程度，并保持电极基质中的内聚力，尽管由于硅合金化引起的体积发生了巨大变化。