Natural cellulose derived nanofibrous Ag-nanoparticle/SnO2/carbon ternary composite as an anodic material for lithium-ion batteries

摘要

A series of nanostructured ternary Ag-nanoparticle/SnO2/carbon (Ag-NP/SnO2/carbon) composite materials with varied contents of silver were synthesized by employing natural cellulose substance (e.g., commercial laboratory filter paper) as both scaffold and carbon source. The nanofibrous SnO2/carbon composite material was first fabricated by a layer-by-layer assembly process followed by subsequent carbonization under argon atmosphere, and the Ag nanoparticles were loaded on the surface of the nanofiber via photocatalytic reduction reaction method by using silver nitrate as the precursor. The resultant composites were composed of carbon nanofibers coated with a thin layer of fine SnO2 nanocrystallites and further silver nanoparticles with the diameter of about 15-20 nm immobilized on the surfaces. When employed as anode materials for lithium-ion batteries, the Ag-NP/SnO2/carbon composites showed enhanced electrochemical performances compared with the hybrid SnO2/carbon material and Ag nanoparticles decorated nanotubular SnO2(Ag-NP/SnO2-NT). The good electrochemical performances of the Ag-NP/SnO2/carbon composites are attributed to the unique three-dimensional buffering network structures of the carbon fiber scaffold, the enhanced electric conductivity derived from the presence of Ag nanoparticles, as well as the synergistic effect of SnO2 and carbon. Meanwhile, it was noticed that the electrochemical performances of the anode materials got better with the increase of the silver content in the composites. For the eletrochemical examinations, the Ag-NP/SnO2/carbon composite with the highest Ag content of 24.5 wt% showed a superior performance with a stable specific capacity of 690 mAh g after 120 charge/discharge cycles at a current density of 100 mA g(-1).