Aqueous emulsion of conductive polymer binders for Si anode materials in lithium ion batteries

Abstract

To combine the advantages of conductive polymer binders and aqueous battery electrode coating processes, a versatile emulsion polymerization method is developed to prepare conductive polymer binder emulsions in water for lithium ion battery applications. These polymer emulsions are used as-is as the binder for silicon containing anode materials. In the resulting electrodes, the binder particles and the active material particles are adhered through “point contact”. Increasing the content of aromatic units in the polymer binders can improve the battery performance. After optimization of the material composition in the electrodes, the batteries can achieve about 880 mAh·g−1 initial capacity for graphite/silicon composite materials at a ratio of 73/15 with about 75% capacity retention after 200 cycles.