| 类球形正交LiMnO2的制备、微结构和电化学性能 |
| Preparation, Microstructure and Electrochemical Properties of Spherical-like Orthorhombic LiMnO2 |
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| 摘要: 以共沉淀法得到的类球形MnCO3为前驱物，制备了类球形正交LiMnO2(So-LiMnO2)，采用XRD、SEM和N2吸附技术对样品进行表征；与非球形正交LiMnO2(No-LiMnO2)进行了对比研究。结果表明：o-LiMnO2的堆垛层错度、结晶状况、颗粒形貌和大小与前驱物的微结构密切相关；在80次电化学循环测试过程中，So-LiMnO2经15次循环可达最大的放电容量152 mAh·g-1，其容量衰减平均每次循环0.58 mAh·g-1；而No-LiMnO2要经过38次循环才能达到最大放电容量128 mAh·g-1，容量衰减平均每次循环高达1.24 mAh·g-1。TEM和EDS分析证明：由一次粒子团聚的类球形So-LiMnO2能有效地抑制电解液对材料的腐蚀、减少Mn的溶解，从而提高了电化学循环能力。 |
| 关键词: 共沉淀法 正交LiMnO2 类球形颗粒 电化学循环能力 |
| 基金项目: |
| Abstract: Spherical-like morphology orthorhombic LiMnO2 (So-LiMnO2) powders were prepared using spherical MnCO3 precursors obtained by a carbonate co-precipitation method. The materials were characterized using XRD, SEM and low temperature nitrogen adsorption desorption. Non-spherical orthorhombic LiMnO2 (No-LiMnO2) powders were also studied for comparison. The characteristics of o-LiMnO2 such as the stacking faults, crystallization, particles morphology and size were significantly dependent on the microstructure of precursors. The electrochemical performances of o-LiMnO2-based cathodes were tested during 80 cycles. The So-LiMnO2 cathode had a maximum capacity of 152 mAh·g-1 on the 15th cycle, and exhibited an average capacity decay of approximately 0.58 mAh·g-1 per cycle. By contrast, the No-LiMnO2 sample had a maximum capacity of 128 mAh·g-1 on the 38th cycle, and experienced an average capacity decay of 1.24 mAh·g-1 per cycle. TEM observation and EDS analysis confirmed that So-LiMnO2 particle, agglomerated by primary particles, could reduce the erosion of positive material by electrolytes and the dissolution of manganese, which results in the enhanced electrochemical cycleability. |
| Keywords: co-precipitation method orthorhombic LiMnO2 spherical-like particle electrochemical cycleability |
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| 范广新,曾跃武,陈荣升,吕光烈.类球形正交LiMnO2的制备、微结构和电化学性能[J].无机化学学报,2007,23(6):963-968. |
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