Hameed A Shahul, Bahiraei Hamed, Reddy M V, Shoushtari Morteza Zargar, Vittal Jagadese J, Ong Chong Kim, Chowdari B V R
Department of Chemistry, National University of Singapore , Singapore 117543.
ACS Appl Mater Interfaces. 2014 Jul 9;6(13):10744-53. doi: 10.1021/am502605s. Epub 2014 Jun 23.
ZnFe2O4 and MgxCu0.2Zn0.82-xFe1.98O4 (where x = 0.20, 0.25, 0.30, 0.35, and 0.40) nanoparticles were synthesized by sol-gel assisted combustion method. X-ray diffraction (XRD), FTIR spectroscopy, Raman spectroscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM), and Brunauer-Emmett-Teller (BET) surface area studies were used to characterize the synthesized compounds. ZnFe2O4 and the doped compounds crystallize in Fd3m space group. The lattice parameter of ZnFe2O4 is calculated to be a = 8.448(3) Å, while the doped compounds show a slight decrease in the lattice parameter with an increase in the Mg content. The particle size of all the compositions are in the range of ∼50-80 nm, and the surface area of the compounds are in the range of 11-12 m(2) g(-1). Cyclic voltammetry (CV), galvanostatic cycling, and electrochemical impedance spectroscopy (EIS) studies were used to investigate the electrochemical properties of the different compositions. The as-synthesized samples at 600 °C show large-capacity fading, while the samples reheated at 800 °C show better cycling stability. ZnFe2O4 exhibits a high reversible capacity of 575 mAh g(-1) after 60 cycles at a current density of 100 mA g(-1). Mg0.2Cu0.2Zn0.62Fe1.98O4 shows a similar capacity of 576 mAh g(-1) after 60 cycles with better capacity retention.
采用溶胶-凝胶辅助燃烧法合成了ZnFe₂O₄和MgₓCu₀.₂Zn₀.₈₂₋ₓFe₁.₉₈O₄（其中x = 0.20、0.25、0.30、0.35和0.40）纳米颗粒。利用X射线衍射（XRD）、傅里叶变换红外光谱（FTIR）、拉曼光谱、扫描电子显微镜（SEM）、透射电子显微镜（TEM）以及布鲁诺尔-埃米特-特勒（BET）比表面积研究对合成的化合物进行了表征。ZnFe₂O₄和掺杂化合物在Fd3m空间群中结晶。计算得出ZnFe₂O₄的晶格参数为a = 8.448(3) Å，而掺杂化合物的晶格参数随Mg含量的增加略有减小。所有组合物的粒径在约50 - 80 nm范围内，化合物的比表面积在11 - 12 m² g⁻¹范围内。采用循环伏安法（CV）、恒电流循环和电化学阻抗谱（EIS）研究来考察不同组合物的电化学性能。在600℃合成的样品表现出大容量衰减，而在800℃再加热的样品表现出更好的循环稳定性。在100 mA g⁻¹的电流密度下循环60次后，ZnFe₂O₄表现出575 mAh g⁻¹的高可逆容量。Mg₀.₂Cu₀.₂Zn₀.₆₂Fe₁.₉₈O₄在循环60次后表现出类似的576 mAh g⁻¹容量且具有更好的容量保持率。
