The water-soluble biopolymers, gelatin and sodium alginate, were investigated as potential alternative binders for use in lithium-ion battery anodes. The polymers were modified using a deep eutectic solvent (DES) made from choline chloride and glycerol. It was found that the addition of the DES resulted in greater plasticity and adhesion with respect to the unmodified binders and also to the current commonly used PVDF or CMC/SBR binders. Both the modified gelatin and sodium alginate binders are dispersible in water and can be rapidly delaminated by using mild ultrasound. These latter points are key steps in the function of the anode material and the subsequent recycling at the end of life. Imaging of the coatings formed using scanning electron microscopy and atomic force microscopy showed that the two types of binders dispersed themselves differently around the graphite particles, with the gelatin binder being distributed across the entire electrode surface, whereas the sodium alginate binder remained located at the hydrophilic edge planes of the graphite.

The integration of lithium-ion batteries (LIB) into transportation through the implementation of hybrid and electric vehicles is driving fundamental research into improving their performance and lifetime. The rapid production of new electric vehicles by several popular brands also raises the question of how much material will eventually need to be reused or recycled. With a combination of an enhanced fundamental analysis of commercially utilized electrodes with fundamental chemical knowledge, answers to the scientific material challenges of lithium ion batteries will aid in not only the implementation of battery powered electrical transport but also the development of end of life recycling processes. Here, using quantitative nanomechanical and conductive atomic force microscopy, which are nondestructive and rapid techniques, the different components of the composite electrode are unveiled at the nanoscale, identifying the mechanism by which the active material binds together and how the conductive network is formed. Changes in the polymer binder network are observed in an aged cell and are shown to affect the mechanical integrity of the electrode structure, which can lead to the failure of the electrode. The links between nanomechanical and macro-mechanical properties were evaluated using a scratch test and optical microscopy to show that the mechanical integrity of the aged cell was weaker than that of the untouched cell.