基于核磁共振技术测量研究锂电池正极导电浆料的分散性

Evaluation of Lithium-battery Conductive Slurry Dispersion byNuclear Magnetic Resonance Technology

采用核磁共振(NMR)技术研究了不同类型导电颗粒制备的锂电池正极导电浆料。通过测量导电浆料的弛豫时间和弛豫谱,发现了在同等研磨分散条件下炭黑浆料的弛豫时间与比表面积(BET)值呈负相关性,且炭黑浆料弛豫谱为单峰结构,说明炭黑更容易得到分散;而碳纳米管(CNT)浆料的弛豫谱全部为多峰结构,说明CNT的分散性较差。研究结果表明,CNT浆料的固含量越大,颗粒的比表面积越大,那么弛豫谱主峰的弛豫时间就越大,主峰信号占比就越低,说明CNT在溶剂中就越容易发生纠缠和团聚。

The positive conductive slurries prepared by different types of conductive particles for lithium batteries are studied by using nuclear magnetic resonance(NMR)technology.By measuring the relaxation time and spectrum of the slurries,it is found that the relaxation time of carbon black slurry is negatively correlated with the BET value under the same grinding dispersion condition,and the relaxation spectrum of carbon black slurry is single-peak structure,indicating that carbon black is more easily dispersed.The relaxation spectra of carbon nanotube(CNT)slurry are all multi-modal,which indicates that the dispersion of CNT is poor.Further research results show that the larger the solid content of CNT slurry,the larger the specific surface area of the particles,the larger the relaxation time of the main peak of the relaxation spectrum,the lower the proportion of the main peak signal,indicating that the CNT is more prone to entanglement and aggregation in the solvent.