Embedding Atomically Dispersed Iron Sites in Nitrogen‐Doped Carbon Frameworks‐Wrapped Silicon Suboxide for Superior Lithium Storage
Xiaotian Guo, Hengyue Xu, Wenting Li, Yang‐Yi Liu, Yuxin Shi, Qing Li, Huan Pang
Abstract
Abstract Silicon suboxide (SiO x ) has attracted widespread interest as Li‐ion battery (LIB) anodes. However, its undesirable electronic conductivity and apparent volume effect during cycling impede its practical applications. Herein, sustainable rice husks (RHs)‐derived SiO 2 are chosen as a feedstock to design SiO x /iron–nitrogen co‐doped carbon (Fe–N–C) materials. Using a facile electrospray‐carbonization strategy, SiO x nanoparticles (NPs) are encapsulated in the nitrogen‐doped carbon (N–C) frameworks decorating atomically dispersed iron sites. Systematic characterizations including high‐angle annular dark‐field scanning transmission electron microscopy (HAADF‐STEM) and X‐ray absorption fine structure (XAFS) verify the existence of Fe single atoms and typical coordination environment. Benefiting from its structural and compositional merits, the SiO x /Fe–N–C anode delivers significantly improved discharge capacity of 799.1 mAh g −1 , rate capability, and exceptional durability, compared with pure SiO 2 and SiO x /N–C, which has been revealed by the density functional theory (DFT) calculations. Additionally, the electrochemical tests and in situ X‐ray diffraction (XRD) analysis reveal the oxidation of Li x Si phase and the storage mechanism. The synthetic strategy is universal for the design and synthesis of metal single atoms/clusters dispersed N–C frameworks encapsulated SiO x NPs. Meanwhile, this work provides impressive insights into developing various LIB anode materials suffering from inferior conductivity and huge volume fluctuations.