Electrochemical performance of doped LiMn2O4 synthesized by used titanium doped electrolytic manganese dioxide
- 化学化工－已发表论文 
A series of Ti-doped, Ti-Ni-doped and Ti-Co-doped spinels were synthesized by solid-state sintering the mixture of the Ti-doped electrolytic manganese dioxides (Ti-EMD) and LiOH-H2O. X-ray powder diffraction patterns, charge-discharge cycles, electrochemical impedance spectroscopy (EIS), Raman spectroscopy and environmental scanning electron microscope techniques were employed to study the doping effect on the electrochemical performance. In the voltage region of 4.6 to 2.5 V, the button cell of the fresh sample, that of the stocked sample stored for 3 months without cycling, that of the charged sample stored for 3 months at the charged state after charge-discharged for 40 cycles, which prepared by used Ti-doped spinel sample sintered at 600 degrees C, were tested the charge-discharged performance and they exhibited the initial capacity of 205, 172 and 175 mAh center dot g-(1), and the capacity fading rate were 20.5%, 12% and 16%, respectively. The titanium doping obviously improves the storage performance of the spinel samples. EIS data shows that the Ti doping keeps the stability of the charger transferring and the solid-state interface resistance for the stocked sample and also decreases these kinds of resistance of the charge-stored sample. Ex-situ XRD patterns shows that the titanium doping improves the stability of the crystal particles of spinel sample. Under the heavy discharge condition, the co-doping of nickel-titanium or cobalt-titanium could not obviously improve the electrochemical performance of the spinel samples. Thus, titanium doping obviously improves the storage performance of the lithium manganese oxides spinels.