Facile preparation of low-cost multifunctional porous binder for silicon anodes in lithium-ion batteries

A novel multifunctional binder (P-ppCMC) with cross-linked and porous structure is simply prepared through partially protonation and template methods for silicon anodes to accommodate the large volume change of silicon and to enhance the lithium-ion diffusion during the charge/discharge process. In this binder, the cross-linked structure, formed through the carboxyl and hydroxyl groups in partially protonated carboxymethyl cellulose, increases the adhesion and mechanical property of binder, buffering the volume variation of silicon during repeated cycles. The porous structure, generated via template approach, enhances the lithium-ion diffusion and tolerates the volume variation of silicon. Therefore, the P-ppCMC binder significantly improves the cycling stability and rate performance of silicon anodes. The silicon anode with P-ppCMC displays a reversible capacity of 1835 mA h g−1 after 200 cycles at a current density of 0.5 A g−1, and a rate capability of 1707 mA h g−1 at 5 A g−1. The P-ppCMC binder also effectively increases the cycling stability of tin anodes.