Structural and Electrochemical Studies on Todorokite/Vernadite as Cathodes for Rechargeable Lithium Ion Batteries

Abstract

利用XRD、TEM、ICP、低速CV以及恒流充放电等方法研究了一种3V锂离子电池阴极材料的结构及其电化学性能.样品主要由大隧道型结构的钡镁锰矿和层状结构的水羟锰矿组成,该样品的微观形貌为层间距约10nm的叠片状结构.Li+在样品中的嵌入脱出过程具有较好的可逆性和循环稳定性.未经提纯的样品前30次循环的放电比容量达到129mAh/g,100次循环后为96mAh/g.材料结构中嵌入隧道及层间的杂质金属阳离子起着结构支撑以及维持材料的微观结构和电化学性能稳定性的作用.XRD,TEM,ICP,low scan_rate CV and charge/discharge tests were carried out for the studies on the structural and electrochemical behavior of a prepared 3 V manganese oxide cathode for rechargeable lithium ion batteries.XRD analysis revealed that the cathode sample is mainly composed of tunneled Todorokite and layered Vernadite.TEM investigation confirmed that the morphology of the sample is a laminated construction with approximate 10nm layer space.The reversibility of Li + removal/intercalation and structural stability of this sample framework to lithium insertion are good in CV and charge/discharge tests. The discharge capacities were found to be about 129mAh/g obtained on first 30 cycles and remained to be 96mAh/g after 100 charge/discharge cycles.The inlaid cations in the tunnel or interlayer made contribution to the structural and electrochemical stability of this manganese oxide cathode framework.作者联系地址:厦门大学固体表面物理化学国家重点实验室Author's Address: State Key Laboratory for Physical Chemistry of Solid Surface, Inst. of Phys. Chem.,Dept.of Chem.,Xiamen Univ.,Xiamen 36100

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