Silicon-doped carbon xerogel with poly(sodium 4-styrenesulfonate) as a novel protective coating and binder

Abstract

Abstract A composite anode comprised of silicon impregnated in a conductive carbon matrix as an anode material is an interesting path to improve the specific energy density of Li-ion batteries. However, the volume variation and SEI instability of silicon during cycling should be avoided to obtain stable electrodes. In the present study, silicon nanoparticles (SiNPs) impregnated in a 3D carbon xerogel matrix are synthesized with an ionically-conductive polymer, poly (sodium-4 styrenesulfonate) (PSS), as either a binder or a protective coating. The physico-chemical and electrochemical properties of this novel composite electrode with PSS as a coating or binder improves the retention of reversible capacity by a factor of five as compared to the same electrode using only a conventional poly (vinylidene difluoride) (PVDF) binder. Indeed, the composites with 10 wt% SiNPs utilizing PSS as a coating or binder retains a specific gravimetric energy density of 450 mAh g−1 composite after 40 cycles. Structural, textural, and electrochemical characteristics as well as prospects for further improvements of this composite anode are discussed.