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Huaifang Shang, and Dingguo Xia, Spinel LiMn2O4 integrated with coating and doping by Sn self-segregation, Int. J. Miner. Metall. Mater., 29(2022), No. 5, pp.909-916. https://dx.doi.org/10.1007/s12613-022-2482-8
Huaifang Shang, and Dingguo Xia, Spinel LiMn2O4 integrated with coating and doping by Sn self-segregation, Int. J. Miner. Metall. Mater., 29(2022), No. 5, pp.909-916. https://dx.doi.org/10.1007/s12613-022-2482-8
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LiMn2O4正极材料表面基于自偏析效应的包覆与掺杂一体化

摘要: 近年来,锂离子二次电池作为便携式电子产品和新能源汽车中重要的储能设备,在现代社会的发展中发挥着至关重要的作用。含钴或镍的层状正极材料具有高容量和高的工作电位,被认为是最有前途的高能锂离子电池阴极材料之一。 然而,由于钴和镍的成本高、资源有限,因此,开发高性能、低成本的正极材料对锂离子电池的发展具有重要意义。尖晶石锰酸锂(LiMn2O4)由于结构稳定、安全性好、运行电压高、成本低,成为商用可充电储能正极材料的主流。然而,由于Jahn–Teller效应引起的锰溶解导致LiMn2O4的容量衰减致使其在电动汽车动力电池中的应用一直受到限制。本文报道了通过Sn的自偏析在LiMn2O4中同时实现包覆和掺杂的结合,通过俄歇电子能谱和软X射线吸收谱的研究表明:包覆层为富Sn的LiMn2O4,而在体相中则有少量Sn掺杂。该整合策略不仅可以缓解Jahn–Teller扭曲,而且可以有效避免锰的溶解。改性后的材料在25°C和55°C条件下测试,其初始容量分别为124 mAh·g−1和120 mAh·g−1,循环50周后容量保持率分别为91.1%和90.2%。这种新型的材料加工方法为锂离子电池正极材料的发展指明了新的方向。

 

Spinel LiMn2O4 integrated with coating and doping by Sn self-segregation

Abstract: The development of high-performance and low-cost cathode materials is of great significance for the progress in lithium-ion batteries. The use of Co and even Ni is not conducive to the sustainable and healthy development of the power battery industry owing to their high cost and limited resources. Here, we report LiMn2O4 integrated with coating and doping by Sn self-segregation. Auger electron energy spectrum and soft X-ray absorption spectrum show that the coating is Sn-rich LiMn2O4, with a small Sn doping in the bulk phase. The integration strategy can not only mitigate the Jahn–Teller distortion but also effectively avoid the dissolution of manganese. The as-obtained product demonstrates superior high initial capacities of 124 mAh·g−1 and 120 mAh·g−1 with the capacity retention of 91.1% and 90.2% at 25°C and 55°C after 50 cycles, respectively. This novel material-processing method highlights a new development direction for the progress of cathode materials for lithium-ion batteries.

 

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