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Zinc Lithium Ion Battery Cathode Material Li The (the Ni <sub> / 3 </ Sub> Co <sub> 1/3 </ Sub> Mn <sub> 1/3 </ Sub>) O <sub> 2 < / Sub> Electrochemical Performance

Posted on:2011-11-03Degree:MasterType:Thesis
Country:ChinaCandidate:X J ZhouFull Text:PDF
GTID:2192330332476649Subject:Materials Physics and Chemistry
Abstract/Summary:PDF Full Text Request
Li(Ni1/3Co1/3Mn1/3)O2 has become a promising cathode material for lithium batteries. The discharge capability and capacity retention at high rate cycles needed to be improved if it was used to power batteries, the performance of cycles also needed to be improved especially at high voltage.The discharge capability was connect to the conduction and Li+ difussing of material at high rate or high voltage. The capacity decreased at cycles, because that RSEI and Rct increased and the stability of SEI membrane in cycles.In this study, Li(Ni1/3Co1/3Mn1/3)O2 doping zinc about 1% and 4% had been synthesized by co-precipitation method. The properties of synthesized materials were studied by charge-discharge of cells, EIS, CV and so on, including the reversible of material,the resistance of SEI membrane and electric charges distracting,Li+ difussing, then analyzing the effects of zinc.In the tests of cells charging and dischargig, the discharging capacity of Li(Ni1/3Co1/3Mn1/3)O2 decreases quickly along of discharfe rate increasing, the trend is controlled by doping proper zinc. The structure and performance of SEI membrane are changed because of doping zinc on the surface of Li(Ni1/3Co1/3Mn1/3)O2, the resistance of Li+ difussing and electric charges distracting are reduced at the same time. But the action is weakened doping more zinc.According EIS at cycles, the formation and stability of SEI membrane are quickened due to doping proper zinc, and the quickly increasing of RSEI and Rct is controlled in cycles, so the trend is weakened that the capacity decreased quickly along of discharge rate or voltage increasing.The action is weakened with more zinc, that doping more zinc is bad for formation and stability of SEI membrane.The coulomb efficiency decreased with discharge rate or voltage increasing, the trend is controlled by doping proper zinc, but the action of zinc is weakened when doping more zinc. The reason is that the mission of cathodic peak and anodic peak decreased after doping proper zinc, the reversibility is improved, more zinc is bad for the reversibility of material.Until now, there are little researchs about the performance of doping zinc. This paper research Li(Ni1/3Co1/3Mn1/3)O2 from doping zinc to its electrochemical performance, the trend is controlled by doping proper zinc that the capacity decreases quickly along of discharfe rate increasing, and the increasing of RSEI and Rct is controlled in cycles, the performance of Li(Ni1/3Co1/3Mn1/3)O2 is improved a little.
Keywords/Search Tags:cathode, Li(Ni1/3Co1/3Mn1/3)O2, zinc, electrochemical impendance spectroscopy, cycle voltage
PDF Full Text Request
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