Layered δ-MnO₂ as positive electrode for lithium intercalation
2011
Du, Guodong | Wang, Jieqiang | Guo, Zaiping | Chen, Zhixin | Liu, Huakun
Layer structured δ-MnO₂ was synthesized by a microwave-assisted hydrothermal method. The morphology of the product consists of flower-like spheres that range from about 200nm to 3μm in diameter and are composed of sheets about 5–10nm in thickness. When tested in the voltage range of 2 to 4.5V vs. Li⁺/Li in coin cells, the separator is blocked, handicapping Li⁺ conductivity and leading to cell failure. When tested in the voltage range of 2 to 4V in ethylene carbonate/dimethyl carbonate (EC/DMC), the δ-MnO₂ delivers an initial reversible capacity of 143.7mAhg⁻¹ and can maintain 120mAhg⁻¹ at the 60th cycle. The δ-MnO₂ electrode shows good cycling stability at different current densities and delivers a discharge capacity of about 90mAhg⁻¹ at 1C, indicating that it is a promising cathode material for lithium ion batteries.
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