Abstract Li2MnO3 is the parent compound and a component of the well-studied Li-rich Mn-based layered materials (xLi2MnO3·(1−x)LiMO2) for high capacity Li-ion batteries. Different combinations of citric acid fuel and metal nitrates (C/N) were used to optimize the electrochemical performance of Li2MnO3 nanoparticles by the solution combustion synthesis. Thermodynamic modelling and thermogravimmetric analysis show that the various C/N molar ratio affected the combustion process and the Li2MnO3 powder characteristics like morphology and crystallinity. The fuel-rich composition (C/N = 0.555) with the highest adiabatic flame temperature produced Li2MnO3 cathode materials with the best electrochemical performance. The influence of sintering temperature on the crystallinity of the Li2MnO3 sample was investigated with high-temperature synchrotron XRD. The Li2MnO3 synthesised at a lower temperature (400oC) had a better initial discharge capacity than the one synthesised at a much higher temperature (800oC) however, it showed far poorer cycling stability. These differences in their electrochemical performance were explained on the basis of their microstructure and morphology. Furthermore, increasing annealing time at 800oC (from 2 to 20 hr) achieved phase pure materials and improved the electrochemical performance of Li2MnO3 powders. This improvement was due to the well defined, developed and larger particles of the samples annealed at longer times. The results show that apart from increasing synthesis temperature, varying annealing times at optimum temperature could be used to improve the functional performance of ceramic oxides.

中文翻译：

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使用溶液燃烧合成优化锂离子电池 Li2MnO3 正极材料的电化学性能：更高和更长的温度合成提高性能

摘要 Li2MnO3 是经过充分研究的高容量锂离子电池富锂锰基层状材料 (xLi2MnO3·(1-x)LiMO2) 的母体化合物和组分。柠檬酸燃料和金属硝酸盐 (C/N) 的不同组合用于通过溶液燃烧合成优化 Li2MnO3 纳米颗粒的电化学性能。热力学模型和热重分析表明，不同的 C/N 摩尔比影响燃烧过程和 Li2MnO3 粉末的形态和结晶度等特性。具有最高绝热火焰温度的富燃料组合物 (C/N = 0.555) 产生具有最佳电化学性能的 Li2MnO3 正极材料。采用高温同步加速器XRD研究了烧结温度对Li2MnO3样品结晶度的影响。在较低温度 (400oC) 合成的 Li2MnO3 比在高得多的温度 (800oC) 合成的 Li2MnO3 具有更好的初始放电容量，但循环稳定性要差得多。它们电化学性能的这些差异是基于它们的微观结构和形态来解释的。此外，在 800oC 下增加退火时间（从 2 小时到 20 小时）可以获得相纯材料并改善 Li2MnO3 粉末的电化学性能。这种改进是由于经过较长时间退火的样品具有明确的、发达的和较大的颗粒。结果表明，除了提高合成温度外，在最佳温度下改变退火时间可用于改善陶瓷氧化物的功能性能。