Thursday, 23 June 2016
Riverside Center (Hyatt Regency)
Recently, the demand for energy storage devices for electricity supply has been increasing remarkably. Lithium-ion batteries have already been popular power supplies for devices such as mobile phones, notebooks, digital devices and hybrid vehicles and so on. This increases the rate of lithium consumption; therefore, its cost has risen because of lithium source problem. Owing to abundant sodium resource and its low cost in comparison with lithium, sodium-ion batteries are promising for energy storage devices. Concerning cathode materials, layered NaxMO2 are classified into two main groups (O3 type or P2 type) in which the sodium ions are accommodated at octahedral and prismatic sites, respectively. Many works reported that P2-type structure exhibits a higher capacity and cyclability than O3-type structure. In this work, P-type Na0.6Mn0.65Ni0.25Co0.10O2 cathode materials were synthesized by a co-precipitation method. Effect of calcination temperature on the morphology, crystalline structure and electrochemical properties were investigated. Both P3-type (700 oC) and P2-type (800-1000 oC) structures were obtained at different calcination temperatures. In the cycling process, the P3-type material revealed a high discharge capacity of 136 mAh g-1 but a poor cycling performance. In contrast, the P2-type synthesized at 900 oC gave a highest specific discharge capacity of 148 mAh g-1and a more stable cycling performance and a good rate capability between 2.1 and 4.3 V.
Acknowledgement
This work was supported by the Human Resource Training Program for Regional Innovation and Creativity through the Ministry of Education and National Research Foundation of Korea (NRF-2014H1C1A1066977).
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