We present a holistic view on the role of polymeric binders in waterborne LiB anodes, including preparation and processing of wet slurries as well as microstructure, electrical conductivity and mechanical integrity of dry electrode layers. We focus on carboxymethyl cellulose (CMC), with respect to technical application the influence of soft, nano-particulate styrene–butadiene rubber (SBR) as secondary binder is also addressed. We discuss the influence of CMC concentration, molecular weight (Mw) and degree of substitution (DS) on flow behavior of anode slurries. Rheological data are not only relevant for processing, here we use them to characterize the adsorption of CMC on active material particles and dispersion of these particles in the slurry at technically relevant concentrations. The fraction of CMC adsorbed onto graphite particles increases with increasing Mw and decreasing DS. Electrical conductivity increases with Mw, i.e. with decreasing free polymer deteriorating conductive carbon black pathways. CMC does not contribute to the adhesion of electrode layers, irrespective of Mw or DS, technically feasible adhesion is inferred by SBR. Cohesive strength of anode layers, determined here for the first time under well-defined mechanical load, increases with increasing Mw and decreasing DS, i.e. with increasing fraction of adsorbed CMC and corresponding improved particle dispersion. Strong cohesion and high electrical conductivity are correlated to an alignment of graphite particles as revealed by electron microscopy, presumably enabled by higher particle mobility in well-dispersed slurries. Accordingly, targeted choice of CMC is a valuable means to control processing, electrical conductivity and mechanical strength of LiB electrodes.

中文翻译：

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羧甲基纤维素对锂离子电池负极浆料流动行为及相应干层电学和机械性能的影响

我们全面介绍了聚合物粘合剂在水性 LiB 负极中的作用，包括湿浆料的制备和加工以及干电极层的微观结构、导电性和机械完整性。我们专注于羧甲基纤维素 (CMC)，在技术应用方面，还解决了柔软的纳米颗粒丁苯橡胶 (SBR) 作为辅助粘合剂的影响。我们讨论了 CMC 浓度、分子量 (Mw) 和取代度 (DS) 对阳极浆料流动行为的影响。流变数据不仅与加工相关，这里我们使用它们来表征 CMC 在活性材料颗粒上的吸附以及这些颗粒在技术相关浓度下在浆料中的分散。CMC 吸附在石墨颗粒上的比例随着 Mw 的增加和 DS 的降低而增加。电导率随 Mw 增加，即随着游离聚合物的减少而恶化导电炭黑通路。CMC 对电极层的附着力没有贡献，无论 Mw 或 DS，技术上可行的附着力由 SBR 推断。阳极层的内聚强度，在明确定义的机械负载下首次确定，随着 Mw 的增加和 DS 的减少而增加，即随着吸附的 CMC 分数的增加和相应改善的颗粒分散。电子显微镜显示，强内聚力和高导电性与石墨颗粒的排列相关，这可能是由于分散良好的浆料中较高的颗粒迁移率所致。因此，