Si nanoparticles embedded in carbon nanofiber sheathed with Li6PS5Cl as an anode material for all-solid-state batteries

Abstract Silicon is an attractive anode material for all-solid-state batteries due to its high theoretical capacity and low working potential. However, the poor cycle stability caused by electrical and ionic contact loss resulting from the severe volume change of the Si associated with Li should be addressed. Here, we report Si nanoparticles embedded in carbon nanofiber (CNF) sheathed with Li6PS5Cl (LPSCl) (Si/CNF@LPSCl) as anode material to achieve high energy density and stable cyclability for all-solid-state batteries. By embedding Si in the CNF, more favorable strain release and robust electronic pathways are available. The conformal coating of solid electrolyte on the surface of Si/CNF composite enhances the interfacial stability between the active material and the solid electrolyte, which leads to the improvement in electrochemical properties by suppressing the contact loss. The Si/CNF@LPSCl composite electrode exhibits a reversible capacity of 1172 mAh g−1 at 0.1C and stable cyclability of 84.3% at 0.5C after 50 cycles. Especially, the concentration of active material (Si/CNF@LPSCl) in the electrode is significantly increased without noticeable performance degradation due to the improved interfacial stability, which enables the increase of the energy density and reduction of the fabrication cost.