Factors Affecting Contact Resistance between Electrode and Current Collector

Contact resistance between the battery film and its current collector should be minimized in order to fully optimize battery electrodes. Increased resistance results from any factor limiting electrons from transitioning between the current collector and porous electrode materials, such as increased pockets of void space, depletion of conductive additive, or formation of resistive corrosion products. This work explores the effect on contact resistance of changes in battery aging, treatment, and film drying rates. The levels of aging include uncycled, lightly cycled, and heavily cycled electrodes. Battery treatment comparison is between the films treated with and without the commonly used oxalic acid [1]. The drying rates are varied through use of three different drying temperatures. Measurement of contact resistance is done using a four-contact microprobe previously utilized by our group [2]. Results from this measurement require a computer model to interpret. We will also compare resistance to peel strength test results. An understanding of conditions affecting contact resistance allows one to decrease contact resistance of battery electrodes during various production stages and know to what degree aging will affect battery performance. [1] Zhi Zhu et al. Journal of Power Sources 224, 13-19 (2012). [2]J.E. Vogel et al. Electrochimica Acta 297, 820-825 (2019).