The magnetic particles of nickel-zinc ferrite with chemical composition Ni1-xZnxFe2O4 were synthesized successfully by citrate precursor auto-combustion method using high purity nitrates and citric acid as chelating a...The magnetic particles of nickel-zinc ferrite with chemical composition Ni1-xZnxFe2O4 were synthesized successfully by citrate precursor auto-combustion method using high purity nitrates and citric acid as chelating agent. The prepared powder of nickel-zinc ferrites was sintered at 1000℃ for 1 hr to obtain good crystalline phase and was used for further study. The X-ray diffraction technique was employed to confirm the single phase formation of nickel ferrite. The X-ray diffraction pattern shows the Bragg’s peak which belongs to cubic spinel structure. The values of lattice constant, X-ray density, bulk density, and porosity were calculated. The temperature dependence of the electrical conductivity plot shows the kink, which can be attributed to ferromagnetic-paramagnetic transition. The activation energy obtained from resistivity plots in paramagnetic region is found to be more than that in ferrimagnetic region. The conduction mechanism in nickel-zinc ferrite particles has been discussed on the basis of hopping of electrons.展开更多
镍钴氢氧化物由于理论比容量高、经济效益良好、来源广泛等优点,被广泛应用于镍锌电池中作为电极材料。本工作采用共沉淀法,调控具有不同镍钴比例的硝酸盐溶液,在室温环境下一步合成镍钴双金属氢氧化物,并将其制备成镍锌电池正极材料。...镍钴氢氧化物由于理论比容量高、经济效益良好、来源广泛等优点,被广泛应用于镍锌电池中作为电极材料。本工作采用共沉淀法,调控具有不同镍钴比例的硝酸盐溶液,在室温环境下一步合成镍钴双金属氢氧化物,并将其制备成镍锌电池正极材料。采用X射线衍射仪(XRD)、X射线光电子能谱(XPS)、扫描电子显微镜(SEM)等对所合成的样品进行表征,观察其微观形貌结构,采用电化学工作站等研究其作为镍锌电池电极材料的电化学性能。研究发现,采用高浓度Na OH溶液作为电解液,比其他通过共沉淀法所制备的镍钴氢氧化物在镍锌电池中所表现出的容量更高。结果表明,当镍钴投料比为4∶1时,样品具有最为出色的容量表现,其中,Ni_(4)Co_(1)-LDH样品在电流密度为0.5 A/g时容量可以达到327.9 m Ah/g。将其作为正极材料、锌箔作为负极,与高浓度的Na OH溶液一起组装成镍锌电池进行电化学测试,在0.5 A/g电流密度下具有230.7 m Ah/g的容量,该研究兼具材料合成快速和性能表现良好等优点,研究结果有望为镍锌电池性能优化提供新思路。展开更多
文摘The magnetic particles of nickel-zinc ferrite with chemical composition Ni1-xZnxFe2O4 were synthesized successfully by citrate precursor auto-combustion method using high purity nitrates and citric acid as chelating agent. The prepared powder of nickel-zinc ferrites was sintered at 1000℃ for 1 hr to obtain good crystalline phase and was used for further study. The X-ray diffraction technique was employed to confirm the single phase formation of nickel ferrite. The X-ray diffraction pattern shows the Bragg’s peak which belongs to cubic spinel structure. The values of lattice constant, X-ray density, bulk density, and porosity were calculated. The temperature dependence of the electrical conductivity plot shows the kink, which can be attributed to ferromagnetic-paramagnetic transition. The activation energy obtained from resistivity plots in paramagnetic region is found to be more than that in ferrimagnetic region. The conduction mechanism in nickel-zinc ferrite particles has been discussed on the basis of hopping of electrons.
文摘镍钴氢氧化物由于理论比容量高、经济效益良好、来源广泛等优点,被广泛应用于镍锌电池中作为电极材料。本工作采用共沉淀法,调控具有不同镍钴比例的硝酸盐溶液,在室温环境下一步合成镍钴双金属氢氧化物,并将其制备成镍锌电池正极材料。采用X射线衍射仪(XRD)、X射线光电子能谱(XPS)、扫描电子显微镜(SEM)等对所合成的样品进行表征,观察其微观形貌结构,采用电化学工作站等研究其作为镍锌电池电极材料的电化学性能。研究发现,采用高浓度Na OH溶液作为电解液,比其他通过共沉淀法所制备的镍钴氢氧化物在镍锌电池中所表现出的容量更高。结果表明,当镍钴投料比为4∶1时,样品具有最为出色的容量表现,其中,Ni_(4)Co_(1)-LDH样品在电流密度为0.5 A/g时容量可以达到327.9 m Ah/g。将其作为正极材料、锌箔作为负极,与高浓度的Na OH溶液一起组装成镍锌电池进行电化学测试,在0.5 A/g电流密度下具有230.7 m Ah/g的容量,该研究兼具材料合成快速和性能表现良好等优点,研究结果有望为镍锌电池性能优化提供新思路。
