Electrode Design from "Internal" to "External" for High Stability Silicon Anodes in Lithium-Ion Batteries.

ABSTRACT

Building a stable electrode structure is an effective way to promote the practical applications of Si anode, which has large volume changes during charge/discharge process, in lithium-ion batteries. Herein, we fabricated an integrated electrode structure reinforced from "internal" to "external" to boost the performance of Si nanoparticles (NPs). The electrode contains the conductive polymer of poly(3,4-ethylene dioxythiophene)poly(styrenesulphonic acid) (PEDOTPSS) as the binder, reduced graphene oxide (rGO), and hydroxylated Si NPs, which help form the "internal" interaction between them through the hydrogen bonding, while the "external" malleable network built by the flexible polymers and two-dimensional rGO sheets as the framework endows the highly flexible network to accommodate the Si expansion and forms long-range conductive network. Thus, the built-integrated electrode by the simple casting method shows high capacity, good rate performance, and long cycling stability. It is noted that such an electrode shows a high areal capacity of 3.29 mA h cm-2 and a high volumetric capacity of 3290 A h cm-3 at 0.09 mA cm-2. The integrated electrode design is promising to promote the practical use of Si anodes and can be extended to other noncarbon anodes with large volume changes.