The battery community has paid significant attention to silicon (Si) as a lithium ion battery (LIB) anode material on account of its exceptional theoretical gravimetric capacity (~4200 mAh g-1), that is approximately 10 times larger than that of the conventional graphite (~370 mAh g-1). High gravimetric capacity of Si is expected to play an important role in bringing many of the key LIB applications to a reality. Despite the advantageous gravimetric capacity, Si suffers from short cycle life originating from its large volume change during repeated Li (de)insertion. Upon full lithiation forming an alloy of Li4.4Si, Si undergoes volume expansion of ~300% with respect to its initial state. While diverse smart electrode designs involving various nanostructured Si have been demonstrated to be effective in mitigating these ruinous mechanisms, the choice of binder has also turned out to affect cell performance significantly. We introduce  a new hyperbranched polymeric binder for Si nanoparticle anodes in lithium ion batteries. This new polymer presents multidimensional hydrogen bonding interactions with each Si particle while promoting a hyperbranched polymeric network that allows self-healing effect. These unique binder properties endow the Si electrode with substantially improved mechanical stability and electrochemical performance compared to conventional linear polymer-based counterparts.

Hyperbranched polymers as effective multidimensional binders for silicon anodes in lithium rechargeable batteries

247th National Meeting (2014)

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