Stable lithium storage of hierarchical Zn2SiO4/C micro-/nanospheres enabled by in-situ introduction of an endogenous Zn4Si2O7(OH)2

Abstract

Zn2SiO4 with high natural abundance and low cost has attracted a lot of attention in lithium-ion battery (LIB) anode realm, but its electrochemical performances are poor (such as short cyclic life and fast capacity decay). Herein, the electrochemical performances of Zn2SiO4 are significantly improved through a novel and simple strategy, including morphological engineering and especially the in-situ introduction of an endogenous Zn4Si2O7(OH)2 by simply regulating the carbonization temperature. The findings show that the conformal carbon-coated ultrathin Zn2SiO4/Zn4Si2O7(OH)2 hybrid nanosheets assembled hierarchical micro-/nanospheres (ZSO/ZSOH@C) are endowed with stable structure, enhanced conductivity, improved Li+ diffusion kinetics and a LiF-rich stable SEI layer during charge/discharge process. Therefore, the ZSO/ZSOH@C anode manifests superior electrochemical performance, with 475.5 and 372.1 mAh g−1 at 200 and 2000 mA g−1 after 350 and 400 cycles, respectively. The structure-property correlations of ZSO/ZSOH@C anode are systematically studied and demonstrate that the characteristically hierarchical structure and the synergistic effects between Zn2SiO4 and Zn4Si2O7(OH)2 are responsible for the superior electrochemical performances of the ZSO/ZSOH@C anode. Finally, this work may inspire ideas for the preparation of high-performance Zn2SiO4 or other silicates for LIB anodes.