Hierarchical Sulfide‐Rich Modification Layer on SiO/C Anode for Low‐Temperature Li‐Ion Batteries

Abstract

Abstract The silicon oxide/graphite (SiO/C) composite anode represents one of the promising candidates for next generation Li‐ion batteries over 400 Wh kg−1. However, the rapid capacity decay and potential safety risks at low temperature restrict their widely practical applications. Herein, the fabrication of sulfide‐rich solid electrolyte interface (SEI) layer on surface of SiO/C anode to boost the reversible Li‐storage performance at low temperature is reported. Different from the traditional SEI layer, the present modification layer is composed of inorganic–organic hybrid components with three continuous layers as disclosed by time‐of‐flight secondary ion mass spectrometry (TOF‐SIMS). The result shows that ROSO2Li, ROCO2Li, and LiF uniformly distribute over different layers. When coupled with LiNi0.8Co0.1Mn0.1O2 cathode, the capacity retention achieves 73% at −20 °C. The first principle calculations demonstrate that the gradient adsorption of sulfide‐rich surface layer and traditional intermediate layer can promote the desolvation of Li+ at low temperature. Meanwhile, the inner LiF‐rich layer with rapid ionic diffusion capability can inhibit dendrite growth. These results offer new perspective of developing advanced SiO/C anode and low‐temperature Li‐ion batteries.

Keywords

• hierarchical layers
• lithium ion batteries
• low temperature
• SiO/C composite anodes
• sulfide‐rich layers