An attempt to use atomic force microscopy for determination of bond type in lithium battery electrodes

Lithium batteries use binders (mostly polymeric) to achieve appropriate mechanical strength of electrodes. The nature of binding between the polymers and the active component, however, is hardly known. In this paper we attempt to establish this nature by using atomic force microscopy (AFM) measurements. In our model study, the interaction between silicon and carboxymethyl cellulose (CMC)-an anode system of considerable practical interest-is studied. We show that, contrary to occasional expectations in the battery community, the use of AFM in such complex systems cannot give direct information about the magnitude of forces between polymer molecules and substrate. Nevertheless, one can use an indirect approach whereby one can tell whether in the particular case strong (e.g. covalent) or weaker (e.g. adsorption) interactions prevail.