(565d) A Novel Scaffold Binder Structure for High Capacity Silicon Anodes of Lithium-Ion Battery

A sodium carboxymethyl cellulose (CMC) scaffold as a binder structure for silicon anodes in Lithium-ion battery will be presented. This three-dimensional (3D) porous CMC matrix provides free volume for Si expansion, thus improving the structural stability. The porous CMC scaffold can also enhance the lithium ion transport in the electrodes, as well as being able to improve the electrochemical reaction kinetics. Our results demonstrated that this noval 3D binder structure remarkably improved the cycling stability and rate performance of the silicon anodes comparing to the ones prepared using the tradional sulrry casting technique. For instance, silicon nano-particles in this scaffold can retain 1678 mAh/g capacity (78% retention) after 150 charge/discharge cycles between 0 and 1.5 V at discharge rate of 0.1 C.

The electrochemical performance of the Si-based anodes with polymer scaffold binder can be further improved by carbonization of the polymer scaffold. The mechanism is currently under investigation. The scaffold binder structure works well for electrodes based on both Si nano-particles and micron-sized Si particles.