鋰離子電池 (LIB) 由多種活性及非活性材料組成，並經多步驟工藝製造而成。材料選擇和製程條件會極大地影響電池的最終性能。特別是電極是其中影響電池性能的最重要組成元件之一。電極品質會直接影響電池的能量密度和電化學性能。

電極的製造非常複雜，需要將活性材料、黏著劑和導電添加劑混合成漿狀，塗佈在金屬電流收集器上。然後對電極進行乾燥和壓延（壓實）。在電極生產過程中，漿料配方需要在儲存過程中保持穩定，易於分散，並具有流動性，以進行均勻的塗佈。為最佳化配方和製程而對漿料進行特性分析，是提升整個電池性能的關鍵步驟。

流變學為在應力作用下，對材料流動和變形的相關研究，在電極漿料的開發和最佳化過程中起著至關重要的作用。如上一篇部落格所述，電池電極漿料流變學涉及測量黏度、觸變性能和降伏應力，這三個關鍵特性可確保適當的塗佈和穩定性。

Another important element of electrode performance is electrical conductivity. Lithium-ion battery cathodes typically include conductive additives such as carbon black particles to compensate for the poor conductivity of the active materials. The carbon black particles agglomerate around the active particles to form a percolation network to conduct electrons to the current collector. The conductive network structure is highly important to the final electrode performance, but shear-induced changes during coating can disrupt the electrically conductive network.

Impedance spectroscopy provides insight on the conductive material dispersion in the slurry but does not account for shear-induced changes from the coating process. Simultaneous rheology and electrochemical impedance spectroscopy directly measure shear-induced changes in the microstructure, replicating slurry coating conditions and enabling measurements of time-dependent recovery after shear. This measurement confirms that the electrically conductive network is maintained in the finished electrode, predicting successful electrode performance prior to full battery assembly.

The new Discovery Hybrid Rheometer Rheo-Impedance Spectroscopy accessory achieves unmatched data quality in both dielectric impedance and rheology measurements. The novel design eliminates the need for electrical contact with the upper tool, which limits the measurement range, and instead positions both electrodes on a lower plate with the insulated upper parallel plate geometry as a conductor. The Rheo-Impedance accessory enables testing across the full range of the DHR’s torque sensitivity, enabling precise characterization of viscosity, yield stress, viscoelasticity, and structure recovery.

Learn more about unlocking complete rheological and impedance measurements of your slurry with the new DHR Rheo-Impedance accessory. For personalized solutions and battery testing guidance, contact TA Instruments experts.