Knowledge Bank

Future generations of battery materials with high energy densities will require the development and selection of new binders in order to maximize battery performance characteristics and lifespan. These binders will need favorable mechanical properties in order to maintain electrode integrity despite volume changes. In this study, the atomic force microscopy method of force spectroscopy is used to measure the mechanical properties of two industry standard binder materials, sodium alginate and polyvinylidene fluoride (PVdF) both in a dry state and immersed in di-methyl carbonate (DMC), a common electrolyte solvent. These samples are examined using a cantilever with a silicon tip in order to determine interphase forces characteristic of a silicon based anode. Both materials experience significant reductions in adhesive force after immersion, but PVdF's adhesive force is reduced so far as to be unmeasurable using the current methodology. Both materials also experience a reduction in Young's modulus, although the elastic modulus of sodium alginate is significantly greater than that of PVdF both before and after immersion. These observations support previous research regarding the properties of these materials and their performance in battery cells and indicate that this methodology can be used for future measurements and comparisons of additional binders.