NiOOH was prepared by one-step electrolysis of spherical Ni(OH)2 and the effects of electrolysis pa-rameters were examined.The highly pure NiOOH was obtained after electrolysis at a current density of 60mA·g-1 an...NiOOH was prepared by one-step electrolysis of spherical Ni(OH)2 and the effects of electrolysis pa-rameters were examined.The highly pure NiOOH was obtained after electrolysis at a current density of 60mA·g-1 and 30℃ with anodic potential controlled in the range of 1.73—1.85V(vs.Zn/ZnO)for 360min.The NiOOH sam-ples were characterized by X-ray powder diffraction(XRD)and scanning electron microscope(SEM)analysis.Re-sults indicate that the electrolysis product is spherical NiOOH doped with graphite.Charge and discharge tests show that the prepared NiOOH offers a discharge capacity of over 270mAh·g-1 at current density of 30mA·g-1 and can be directly used as cathode material of alkaline Zn/NiOOH batteries.Galvanostatic charge/discharge and cyclic volt-ammetry(CV)tests reveal good cycling reversibility of the NiOOH electrode.展开更多
以石墨烯、Ni SO4、K2S2O8(饱和)、氨水、蒸馏水为反应物,经过常温回流制备得到Ni OOH/Ni(OH)2含量不同的石墨烯/Ni OOH/Ni(OH)2复合材料。扫描电子显微镜法(SEM)表征显示,Ni(OH)2/Ni OOH在石墨烯表面上形成多孔结构,负载了多孔Ni OOH/N...以石墨烯、Ni SO4、K2S2O8(饱和)、氨水、蒸馏水为反应物,经过常温回流制备得到Ni OOH/Ni(OH)2含量不同的石墨烯/Ni OOH/Ni(OH)2复合材料。扫描电子显微镜法(SEM)表征显示,Ni(OH)2/Ni OOH在石墨烯表面上形成多孔结构,负载了多孔Ni OOH/Ni(OH)2的石墨烯又进行了层层堆积。电化学性能测试显示,电极材料GP/Ni-5性能最佳,其在电流密度为100 m A/g时,首次可逆比容量为1 287.4 m Ah/g,80次循环后比容量保持在830 m Ah/g,而纯Ni OOH/Ni(OH)2首次可逆比容量为2 400.6 m Ah/g,80次循环后比容量已降至405.9 m Ah/g,表明石墨烯的加入大大提高了材料的稳定性。展开更多
NiOOH was prepared by chemical oxidation of β Ni(OH) 2. The physical characteristics and the chemical composition of the product were characterized by XRD, TG/DTA and ICP measurements. β NiOOH and the mixed samples ...NiOOH was prepared by chemical oxidation of β Ni(OH) 2. The physical characteristics and the chemical composition of the product were characterized by XRD, TG/DTA and ICP measurements. β NiOOH and the mixed samples of β NiOOH with γ MnO 2 in different ratios were charged/discharged in constant current, the results show that the addition of γ MnO 2 improves the discharge voltage plateau of nickel electrode and the optimum ratio of γ MnO 2 in the electrode is 25%. The cut off voltage of nickel electrode should be above 0 V( vs .Hg/HgO).展开更多
Transition metal chalcogenides will be in situ transformed into metal oxyhydroxides during oxygen evolution reaction(OER) process in alkaline medium.However,most of these compounds only undergo surface reconstruction ...Transition metal chalcogenides will be in situ transformed into metal oxyhydroxides during oxygen evolution reaction(OER) process in alkaline medium.However,most of these compounds only undergo surface reconstruction under operating conditions,which contains a large percentage of inactive atoms in the core,thus limiting the exposure of the active sites.Here,we synthesize a Ni-Mo-Se precatalyst with three-dimensional hierarchical structure and develop a facile on-site electrochemical activation strategy for achieving deep reconstruction of the precatalyst.Using the combination of multiple spectroscopic characterizations and high resolution electron microscopy techniques,we unravel that the Ni-Mo-Se precatalyst is deeply reconstructed into γ-NiOOH with co-leaching of Mo and Se after the anodic oxidation.Such flower-like γ-NiOOH is constituted by distorted ultrathin nanosheets with a thickness of ~4.5 nm and contains abundant intercalated species such as water and OH^(-)/CO_(3)^(2-) thus offering a large quantity of accessible active sites.To reach the current density of 10 mA cm^(-2),the derived electrode requires an overpotential of only 244 mV,outperforming almost all the reported analogues.This work highlights the reconstruction chemistry and provides a simple method for the preparation of efficient OER electrocatalyst.展开更多
文摘NiOOH was prepared by one-step electrolysis of spherical Ni(OH)2 and the effects of electrolysis pa-rameters were examined.The highly pure NiOOH was obtained after electrolysis at a current density of 60mA·g-1 and 30℃ with anodic potential controlled in the range of 1.73—1.85V(vs.Zn/ZnO)for 360min.The NiOOH sam-ples were characterized by X-ray powder diffraction(XRD)and scanning electron microscope(SEM)analysis.Re-sults indicate that the electrolysis product is spherical NiOOH doped with graphite.Charge and discharge tests show that the prepared NiOOH offers a discharge capacity of over 270mAh·g-1 at current density of 30mA·g-1 and can be directly used as cathode material of alkaline Zn/NiOOH batteries.Galvanostatic charge/discharge and cyclic volt-ammetry(CV)tests reveal good cycling reversibility of the NiOOH electrode.
文摘以石墨烯、Ni SO4、K2S2O8(饱和)、氨水、蒸馏水为反应物,经过常温回流制备得到Ni OOH/Ni(OH)2含量不同的石墨烯/Ni OOH/Ni(OH)2复合材料。扫描电子显微镜法(SEM)表征显示,Ni(OH)2/Ni OOH在石墨烯表面上形成多孔结构,负载了多孔Ni OOH/Ni(OH)2的石墨烯又进行了层层堆积。电化学性能测试显示,电极材料GP/Ni-5性能最佳,其在电流密度为100 m A/g时,首次可逆比容量为1 287.4 m Ah/g,80次循环后比容量保持在830 m Ah/g,而纯Ni OOH/Ni(OH)2首次可逆比容量为2 400.6 m Ah/g,80次循环后比容量已降至405.9 m Ah/g,表明石墨烯的加入大大提高了材料的稳定性。
文摘NiOOH was prepared by chemical oxidation of β Ni(OH) 2. The physical characteristics and the chemical composition of the product were characterized by XRD, TG/DTA and ICP measurements. β NiOOH and the mixed samples of β NiOOH with γ MnO 2 in different ratios were charged/discharged in constant current, the results show that the addition of γ MnO 2 improves the discharge voltage plateau of nickel electrode and the optimum ratio of γ MnO 2 in the electrode is 25%. The cut off voltage of nickel electrode should be above 0 V( vs .Hg/HgO).
基金supported by the grants from the Natural Science Foundation of China (22072062)。
文摘Transition metal chalcogenides will be in situ transformed into metal oxyhydroxides during oxygen evolution reaction(OER) process in alkaline medium.However,most of these compounds only undergo surface reconstruction under operating conditions,which contains a large percentage of inactive atoms in the core,thus limiting the exposure of the active sites.Here,we synthesize a Ni-Mo-Se precatalyst with three-dimensional hierarchical structure and develop a facile on-site electrochemical activation strategy for achieving deep reconstruction of the precatalyst.Using the combination of multiple spectroscopic characterizations and high resolution electron microscopy techniques,we unravel that the Ni-Mo-Se precatalyst is deeply reconstructed into γ-NiOOH with co-leaching of Mo and Se after the anodic oxidation.Such flower-like γ-NiOOH is constituted by distorted ultrathin nanosheets with a thickness of ~4.5 nm and contains abundant intercalated species such as water and OH^(-)/CO_(3)^(2-) thus offering a large quantity of accessible active sites.To reach the current density of 10 mA cm^(-2),the derived electrode requires an overpotential of only 244 mV,outperforming almost all the reported analogues.This work highlights the reconstruction chemistry and provides a simple method for the preparation of efficient OER electrocatalyst.
