| Owing to spinel3d tunnel structure consisted of tetrahedron and octahedron,lithium manganate has its own advantage such as excellent rate capability, butunfortunately it exhibit poor cycling performance due to structural change duringcharge-discharge process. In this study, Special structure design and doping with otherions are introduced to improve cycling performance of lithium manganate.Citric acid was used as complexing agent to prepared the precursor, and then theprecursor was sintered step-by-step to form a pure spinel lithium manganate. The effectof experimental conditions on the properties of materials has been studied. Further, thesponge-like lithium manganate was prepared using PAA-grafted sponge as templates. Ata current density of0.5C, the electrode shows an initial charge and dischare capacity of107mAh g-1and98mAh g-1, respectively. It exhibit a capacity rentention of81.6%after50cycles, showing a better cycling performance.Lithium manganate was respectively doped with Al3+and F-. The doped lithiummanganate electrodes exhibit best performance When the doping content of Al3+was5wt%. It shows an initial charge and discharge capacity of114.3mAh g-1and104.2mAh g-1respectively at current density of0.3C. And the capacity rentention is89.5%after50cycles. Furthermore, we find that F-doping can not improve the cyclingperformance of lithium manganate electrode.By doping Al3+and F-together, improved cycling performance was obtained forlithium manganate electrodes. At a current rate of0.3C, the lithium manganate electrodewith7.5wt%of Al3+and2.5wt%of F-1shows an initial charge and discharge capacityof121.1mAh g-1and112.2mAh g-1with a capacity rentention of95.3%after50cycles. The average potential of discharge plat is about0.08V higher，and thecharacteristic double-plat have changed to one plat, indicating a steady dischargeprocess.Through3D sponge-like structure design and Al3+and F-1doping, the cyclingperformance of lithium manganate electrode is improved in some degree. |
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