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2006

Chemistry

Electrochemical performance

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Effect Of Ti Doping On The Structure And Performance Of Lini_(0.75)Co_(0.25)O_(2), Hui He, Xuan Cheng, Zhang Ying Aug 2006

Effect Of Ti Doping On The Structure And Performance Of Lini_(0.75)Co_(0.25)O_(2), Hui He, Xuan Cheng, Zhang Ying

Journal of Electrochemistry

In this study,a series of Co-doped compounds with the formula of LiNi_((0.75-x))Co_(0.25)Ti_(x)O_(2)(x=0,(0.1),0.25)was synthesized by using sol-gel method.Their structure,particle size,electrochemical properties were studied by TG,XRD,SEM and electrochemical tests.It was shown that the structure of materials changed from a hexagonal layered structure to a cubic structure as the x value increased.In particular,a mixture of hexagonal and cubic structure was presented at x =0.25.The electrochemical performance of the materials depended strongly on the amount of Ti doping.Possible effects on the structure and performance of LiNi_((0.75-x))Co_(0.25)Ti_(x)O_(2) due to Ti doping are briefly discussed based upon the experiment and computational results.


Effects On The Structure And Electrochemical Performance Of Lifepo_(4) By Zr~(4+) Doping, Yan-Li Ruan, Zhi-Yuan Tang Aug 2006

Effects On The Structure And Electrochemical Performance Of Lifepo_(4) By Zr~(4+) Doping, Yan-Li Ruan, Zhi-Yuan Tang

Journal of Electrochemistry

Stoichiometric Zr-doped lithium iron phosphate(LiFePO_(4)) cathode material was synthesized by a solid-state reaction in an inert atmosphere.The effects of doping content on the physical and electrochemical properties of as-synthesized cathode materials were investigated.The samples were characterized by powder X-ray diffraction(XRD),and their electrochemical performance was systematically measured by impedance response and constant current charge/discharge cycling tests.The results indicate that the low concentration Zr~(4+)doping does not affect the structure of the material but considerably improves its kinetics in terms of capacity delivery and cycle performance.At 0.1C discharging rate,the reversible specific capacities of the Li_(0.99)Zr_(0.01)FePO_(4)cathode material is 135.6mAh g~(-1).After 30 cycles,the capacity fade …


The Influence Of Pva As Disperser On Lifepo_(4) Synthesized By Hydrothermal Reaction, Hui-Lin Li, Hui Zhan Aug 2006

The Influence Of Pva As Disperser On Lifepo_(4) Synthesized By Hydrothermal Reaction, Hui-Lin Li, Hui Zhan

Journal of Electrochemistry

LiFePO_(4) was synthesized by means of hydrothermal reaction,in which PVA acts as disperser and glucose as carbon source.The samples were characterized by X-ray diffraction,scanning electron microscopy and electrochemical measurement.SEM results show that the sample is homogeneously composed of grains with a particle size of ca.200nm.In the charge/discharge test,the products exhibited a 3.45V discharge voltage plateau and a maximum specific capacity of 140mAh/g.After 40 cycles,its capacity only declined by 2.1%.Besides these,the mechanism for the influence of the particle size and carbon coating on the electrochemical property of LiFePO_(4)material was discussed in detail.


Structure And Properties Of Electrodeposited Sn-Co Alloy Electrodes As Anode Material For Lithium-Ion Secondary Batteries, Hong-Hong Jiang, Ling Huang May 2006

Structure And Properties Of Electrodeposited Sn-Co Alloy Electrodes As Anode Material For Lithium-Ion Secondary Batteries, Hong-Hong Jiang, Ling Huang

Journal of Electrochemistry

The Sn-Co alloy deposits were prepared by electroplating.The structure and electrochemical performance of the electroplated Sn-Co alloys have been investigated in detail.Experimental results show that the porous Sn-Co alloy film exhibits hexagonal solid solution,with Sn as the solvent, Co as the solute.The texture of the Sn-Co alloy coating exhibits(110) preferred orientation.Electrochemical tests show that the porous Sn-Co alloy coating electrodes can deliver a discharge capacity of 643mAh/g in the first cycle.At the 20~(h) cycle the charge was 461mAh/g.At initial charge curve the irreversible capacity is probably associated to a combination of processes,which may include the reduction of small amount of …