The effect of doping on the electrochemical performance was studied for spinel type Li1.02MxMn2-xQyO4-y used as cathode material in lithium-ion battery. TG/DTA curves of the precursor (the raw materials) doped with di...The effect of doping on the electrochemical performance was studied for spinel type Li1.02MxMn2-xQyO4-y used as cathode material in lithium-ion battery. TG/DTA curves of the precursor (the raw materials) doped with different elements were studied. The spinel materials Li1.02Mn2O4, Li1.02Co0.02Cr0.01La0.01Mn1.96F0.02O3.98, Li1.02Co0.02Cr0.01 La0.01Mn1.96Cl0.02O3.98, Li1.02Co0.02La1.02Mn1.97Cl0.02O3.98, Li1.02Co0.02Cr0.01Mn1.97O4, were prepared by solid-state reaction method after the pretreatment of conversion under low temperature and uniform mixing. X-ray diffraction patterns showed that all the samples had perfect spinel structure. SEM indicated that the particles of the samples had uni- form size and were distributed evenly. The results of the charge/discharge curves showed that Li1.02Co0.02Cr0.01La0.01Mn1.96F0.02O3.98 had better performance than other materials according to the inhibition of decline of reversible capacity of spinel Li1.02MxMn2-xQyO4-y. Therefore, cycle performance had been improved so obviously that 93.9% of the initial capacity were preserved after 100 cycles. Furthermore, electrochemical impedance tests were carried out with the spinel Li1.02Co0.02Cr0.01La0.01Mn1.96F0.02O3.98 as working electrode, Lithium as counter elec- trode and reference electrode. Results showed that this material possessed good charge/discharge reversible capa- bility and had the lowest impedance in 3.95￣4.25 V range (on the stage of charge / discharge).展开更多
Improvement of elevated-temperature performance of Li1.02Cr0.1Mn1.9O4 cathode material by silicious surface modification was studied. The Li1.02Cr0.1Mn1.9O4 cathode material was treated by silanes coupling agent and t...Improvement of elevated-temperature performance of Li1.02Cr0.1Mn1.9O4 cathode material by silicious surface modification was studied. The Li1.02Cr0.1Mn1.9O4 cathode material was treated by silanes coupling agent and then heated at 580 ℃ to remove organic material. The structures of the modified and unmodified Li1.02Cr0.1Mn1.9O4 were characterized by SpectraPlus, SEM and XRD. The results show that the surface layer of Li1.02Cr0.1Mn1.9O4 material is found to be rich in silicious compound. X-ray diffraction show that all the samples have perfect spinel structure. The electrochemical characterization of modified Li1.02Cr0.1Mn1.9O4 cathode material was tested. The cycle stability of charge/discharge at 55℃ is improved. The results of the charge/discharge curves show that the modified Li1.02Cr0.1Mn1.9O4 has better performance than those unmodified according to the inhibition of decline of reversible capacity of spinel Li1.02Cr0.1Mn1.9O4. Therefore, cycle performance is improved so obviously that 86.03% of the initial capacity is preserved after 100 cycles.展开更多
文摘The effect of doping on the electrochemical performance was studied for spinel type Li1.02MxMn2-xQyO4-y used as cathode material in lithium-ion battery. TG/DTA curves of the precursor (the raw materials) doped with different elements were studied. The spinel materials Li1.02Mn2O4, Li1.02Co0.02Cr0.01La0.01Mn1.96F0.02O3.98, Li1.02Co0.02Cr0.01 La0.01Mn1.96Cl0.02O3.98, Li1.02Co0.02La1.02Mn1.97Cl0.02O3.98, Li1.02Co0.02Cr0.01Mn1.97O4, were prepared by solid-state reaction method after the pretreatment of conversion under low temperature and uniform mixing. X-ray diffraction patterns showed that all the samples had perfect spinel structure. SEM indicated that the particles of the samples had uni- form size and were distributed evenly. The results of the charge/discharge curves showed that Li1.02Co0.02Cr0.01La0.01Mn1.96F0.02O3.98 had better performance than other materials according to the inhibition of decline of reversible capacity of spinel Li1.02MxMn2-xQyO4-y. Therefore, cycle performance had been improved so obviously that 93.9% of the initial capacity were preserved after 100 cycles. Furthermore, electrochemical impedance tests were carried out with the spinel Li1.02Co0.02Cr0.01La0.01Mn1.96F0.02O3.98 as working electrode, Lithium as counter elec- trode and reference electrode. Results showed that this material possessed good charge/discharge reversible capa- bility and had the lowest impedance in 3.95￣4.25 V range (on the stage of charge / discharge).
文摘Improvement of elevated-temperature performance of Li1.02Cr0.1Mn1.9O4 cathode material by silicious surface modification was studied. The Li1.02Cr0.1Mn1.9O4 cathode material was treated by silanes coupling agent and then heated at 580 ℃ to remove organic material. The structures of the modified and unmodified Li1.02Cr0.1Mn1.9O4 were characterized by SpectraPlus, SEM and XRD. The results show that the surface layer of Li1.02Cr0.1Mn1.9O4 material is found to be rich in silicious compound. X-ray diffraction show that all the samples have perfect spinel structure. The electrochemical characterization of modified Li1.02Cr0.1Mn1.9O4 cathode material was tested. The cycle stability of charge/discharge at 55℃ is improved. The results of the charge/discharge curves show that the modified Li1.02Cr0.1Mn1.9O4 has better performance than those unmodified according to the inhibition of decline of reversible capacity of spinel Li1.02Cr0.1Mn1.9O4. Therefore, cycle performance is improved so obviously that 86.03% of the initial capacity is preserved after 100 cycles.
