Binary Network of Conductive Elastic Polymer Constraining Nanosilicon for a High-Performance Lithium-Ion Battery.

Abstract

Silicon-based anodes are attracting more interest in both science and industry due to their high energy density. However, the traditional polymeric binder and carbon additive mixture cannot successfully accommodate the huge volume change and maintain good conductivity when cycling. Herein, we report a multifunctional polymeric binder (PPTU) synthesized by the cross-linking of conducting polymer (PEDOT:PSS) and stretchable polymer poly(ether-thioureas) (PETU). The multifunctional polymeric binder could be curved on the surfaces of nanosilicon particles, forming an interweaving continuous three-dimensional network, which is beneficial to electron transfer and the mechanical stability. Furthermore, the binder is elastic and adhesive, and which can accommodate the huge volume change of silicon to keep its integrity. Utilizing this multifunctional polymeric binder instead of commercial poly(acrylic acid) binder and carbon black mixtures, the nanosilicon anode demonstrates enhanced cycling stability (2081 mAhg-1 after 300 cycles) and rate performance (908 mAhg-1 at 8 Ag-1). The multifunctional polymeric binder has high conductivity, elasticity, and self-healing properties is a promising binder to promote progress toward a high performance lithium-ion battery.