Synthesis Of SnO₂ Nanomaterials By Liquid Phase Method And Their Gas Sensing And Energy Storage Properties

As an n-type wide band gap semiconductor material,SnO2 has broad application prospects in the field of gas sensors,lithium ion batteries,and solar cells,etc.The size,morphology and structure of SnO2 materials are important factors which affect their application performances.It has great significance to achieve the controllable preparation and performance adjustment by exploring different synthetic methods,study on the variation regularities of the material microstructures and morphologies and revealing the relationship between their properties and performances.In this paper,the SnO2 micro-nanometer materials were synthesized by liquid phase method,and their gas sensing and lithium storage performances were investigated.The research contents are as follows:(1)The core-shell structure SnO2 microspheres with the diameter of about 2?m were synthesized by hydrothermal method,which were composed of nanoparticles inside and nanocones outside,and its possible formation mechanism was explored.The gas sensing performances were investigated.The SnO2 microspheres could response to nine kinds of gases such as HCHO,C2H5OH,CH4 and H2S5 etc.Moreover,the SnO2 microspheres exhibited excellent selectivity for HCHO with a detection limit as low as 2 ppm under the operating temperature of260 ?.The lithium storage performances of the microspheres were also studied.The initial discharge specific capacity was 1865.6 mAh g-1 at the current density of 200 mA g-1.After 50 cycles of the charge-discharge,the discharge specific capacity of the SnO2 microspheres was maintained at about 245.7 mAhg-1.(2)SnO2 nanoparticles were synthesized by sol-gel method using SiO2 microspheres as the carrier.After heat treatment at 600 ? for 2 h,the SiO2 was washed out by HF to obtain SnO2 nanoparticles.The average particle size of the obtained SnO2 nanoparticles was 3.3 xn,smaller than that of the SnO2 nanopartieles(?6.4 nm)prepared by calcining the pure hydrous SnO2 at 600 ?.The mechanism of SiO2 inhibiting the growth of SnO2 nanoparticles was studied by Raman spectra,and it was considered to be the compressive stress between SnO2 and the surface of SiO2.The gas sensing performances test showed that the sensitivities and response/recovery times of the obtained 3.3 nm SnO2 nanoparticles were better than 6.4 nm SnO2 nanoparticles.The specific capacity and cycle performance of 3.3 nm SnO2 nanocrystals were also better than 6.4 nm SnO2 nanoparticles.The discharge specific capacity of 3.3 nm SnO2 nanoparticles was maintained at 160 mAh g-after 100 cycles at a current density of 100 mAg-1.