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Rim H.,ASE Korea | Ryoung Park H.,Chonnam National University | Youp Song M.,Chonbuk National University
Ceramics International | Year: 2013

LiNi1-yCoyO2 (y=0.1, 0.3 and 0.5) cathode materials were synthesized by a solid-state reaction method at different temperatures using Li2CO3 as a Li source, NiCO3 as a Ni source, and Co3O4 as a Co source. The electrochemical properties of the synthesized samples were then investigated. Structures of the synthesized LiNi1-yCoyO2 (y=0.1, 0.3 and 0.5) samples were analyzed, and microstructures of the samples were observed. Voltage vs. x in LixNi1-yCo yO2 curves for the first and second charge-discharge cycles and intercalated and deintercalated Li quantity Δx were studied. LiNi0.9Co0.1O2 synthesized at 800 °C had the largest first discharge capacity (152 mAh/g) and quite good cycling performance, with a discharge capacity of 146 mAh/g at n=5. It had a discharge capacity fading rate of 1.4 mAh/g/cycle. © 2012 Elsevier Ltd and Techna Group S.r.l. Source


Rim H.,ASE Korea | Ryoung Park H.,Chonnam National University | Youp Song M.,Chonbuk National University
Ceramics International | Year: 2013

Cathode active materials with a composition of LiNi0.9Co 0.1O2 were synthesized by a solid-state reaction method at 850°C using Li2CO3, NiO or NiCO3, and CoCO3 or Co3O4, as the sources of Li, Ni, and Co, respectively. Electrochemical properties, structure, and microstructure of the synthesized LiNi0.9Co0.1O2 samples were analyzed. The curves of voltage vs. x in LixNi0.9Co 0.1O2 for the first charge-discharge and the intercalated and deintercalated Li quantity Δx were studied. The destruction of unstable 3b sites and phase transitions were discussed from the first and second charge-discharge curves of voltage vs. x in LixNi 0.9Co0.1O2. The LiNi0.9Co 0.1O2 sample synthesized from Li2CO 3, NiO, and Co3O4 had the largest first discharge capacity (151 mA h/g), with a discharge capacity deterioration rate of -0.8 mA h/g/cycle (that is, a discharge capacity increasing 0.8 mA h/g per cycle). © 2013 Elsevier Ltd and Techna Group S.r.l. Source


Rim H.,ASE Korea | Park H.R.,Chonnam National University | Song M.Y.,Chonbuk National University
Ceramics International | Year: 2012

LiNi 1-yCo yO 2 (y = 0.1, 0.3 and 0.5) were synthesized by solid state reaction method at 800 °C and 850 °C from Li 2CO 3, NiO and CoCO 3 as starting materials. The electrochemical properties of the synthesized LiNi 1-yCo yO 2 were investigated. As the content of Co decreases, particle size decreases rapidly and particle size gets more homogeneous. When the particle size is compared at the same composition, the particles synthesized at 850 °C are larger than those synthesized at 800 °C. Among LiNi 1-yCo yO 2 (y = 0.1, 0.3 and 0.5) synthesized at 850 °C, LiNi 0.7Co 0.3O 2 has the largest intercalated and deintercalated Li quantity Δx at the first charge-discharge cycle, followed in order by LiNi 0.9Co 0.1O 2 and LiNi 0.5Co 0.5O 2. LiNi 0.7Co 0.3O 2 synthesized at 850 °C has the largest first discharge capacity (142 mAh/g), followed in order by LiNi 0.9Co 0.1O 2 synthesized at 850 °C (113 mAh/g), and LiNi 0.5Co 0.5O 2 synthesized at 800 °C (109 mAh/g). © 2012 Elsevier Ltd and Techna Group S.r.l. All rights reserved. Source


Song M.Y.,Chonbuk National University | Rim H.,ASE Korea | Park H.R.,Chonnam National University | Mumm D.R.,University of California at Irvine
Ceramics International | Year: 2013

LiNi1-yCoyO2 (y=0.1, 0.3, and 0.5) were synthesized by a solid-state reaction method at 800 °C and 850 °C using Li2CO3, NiO, and Co3O4 as the starting materials. The electrochemical properties of the synthesized LiNi 1-yCoyO2 were then investigated. For samples with the same composition, the particles synthesized at 850 °C were larger than those synthesized at 800 °C. The particles of all the samples synthesized at 850 °C were larger than those synthesized at 800 °C. LiNi0.5Co0.5O2 synthesized at 850 °C had the largest first discharge capacity (159 mA h/g), followed in order by LiNi0.7Co0.3O2 synthesized at 800 °C (158 mA h/g) and LiNi0.9Co0.1O2 synthesized at 850 °C (151 mA h/g). LiNi0.9Co0.1O2 synthesized at 850 °C had the best cycling performance with discharge capacities of 151 mA h/g at n=1 and 156 mA h/g at n=5. © 2012 Elsevier Ltd and Techna Group S.r.l. Source


Song M.Y.,Chonbuk National University | Rim H.,ASE Korea | Park H.R.,Chonnam National University
Ceramics International | Year: 2013

Cathode active materials with a composition of LiNi0.9Co 0.1O2 were synthesized by a solid-state reaction method at 800 C using Li2CO3, NiO or NiCO3, and CoCO3 or Co3O4 as the sources of Li, Ni, and Co, respectively. The electrochemical properties of the synthesized samples were then investigated. The structure of the synthesized LiNi0.9Co 0.1O2 was analyzed, and the microstructures of the samples were observed. The curves of voltage vs. x in LixNi 0.9Co0.1O2 for the first charge-discharge and the intercalated and deintercalated Li quantity Δx were studied. The LiNi0.9Co0.1O2 sample synthesized from Li 2CO3, NiCO3, and Co3O4 had the largest first discharge capacity (152 mAh/g), with a discharge capacity deterioration rate of 1.4 mAh/g/cycle. © 2013 Elsevier Ltd and Techna Group S.r.l. Source

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