Relying on a solvent thermal method, spherical Na2Li2Ti6O14 was synthesized. All samples prepared by this method are hollow and hierarchical structures with the size of about 2-3 μtm, which are assembled by many prim...Relying on a solvent thermal method, spherical Na2Li2Ti6O14 was synthesized. All samples prepared by this method are hollow and hierarchical structures with the size of about 2-3 μtm, which are assembled by many primary nanoparticles （-300nm）. Particle morphology analysis shows that with the increase of temperature, the porosity increases and the hollow structure becomes more obvious. Na2Li2Ti6Ol4 obtained at 800℃ exhibits the best electro- chemical performance among all samples. Charge-discharge results show that Na2Li2Ti6O14 prepared at 800℃ can delivers a reversible capacity of 220.1, 181.7, 161.6, 144.2, 118.1 and 97.2 mA h g-1 at 50, 140, 280, 560, 1400, 2800 mA g-1. How- ever, Na2Li2Ti6O4-bulk only delivers a reversible capacity of 187, 125.3, 108.3, 88.7, 69.2 and 54.8 mA h g-1 at the same current densities. The high electrochemical performances of the as-prepared materials can be attributed to the distinctive hollow and hierarchical spheres, which could effectively reduce the diffusion distance of Li ions, increase the con- tact area between electrodes and electrolyte, and buffer the volume changes during Li ion intercalation/deintercalation processes.展开更多
基金supported by the National Natural Science Foundation of China (21301052 and 51404002)Natural Science Foundation of Heilongjiang Province (E2016056)+2 种基金Specialized Research Fund for the Doctoral Program of Higher Education (20132301120001)Postdoctoral Science-Research Developmental Foundation of Heilongjiang Province (LBH-Q13138)Applied Technology Research and Development Program of Harbin (2015RAQXJ032)
文摘Relying on a solvent thermal method, spherical Na2Li2Ti6O14 was synthesized. All samples prepared by this method are hollow and hierarchical structures with the size of about 2-3 μtm, which are assembled by many primary nanoparticles （-300nm）. Particle morphology analysis shows that with the increase of temperature, the porosity increases and the hollow structure becomes more obvious. Na2Li2Ti6Ol4 obtained at 800℃ exhibits the best electro- chemical performance among all samples. Charge-discharge results show that Na2Li2Ti6O14 prepared at 800℃ can delivers a reversible capacity of 220.1, 181.7, 161.6, 144.2, 118.1 and 97.2 mA h g-1 at 50, 140, 280, 560, 1400, 2800 mA g-1. How- ever, Na2Li2Ti6O4-bulk only delivers a reversible capacity of 187, 125.3, 108.3, 88.7, 69.2 and 54.8 mA h g-1 at the same current densities. The high electrochemical performances of the as-prepared materials can be attributed to the distinctive hollow and hierarchical spheres, which could effectively reduce the diffusion distance of Li ions, increase the con- tact area between electrodes and electrolyte, and buffer the volume changes during Li ion intercalation/deintercalation processes.
