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首次报道了一种新颖的基于乙醇溶液的一步草酸共沉淀法合成富锂锰基正极材料的方法。在这种方法中,包括锂元素在内的所有元素均能在共沉淀反应步骤发生沉淀反应,以此实现更为均匀的元素混合。此外,相比传统的草酸铵共沉淀法,该法省略了前驱体初烧的步骤,节约了合成的时间和成本。通过X射线衍射(XRD)、扫描电子显微镜(SEM)和电化学测试等检测手段表征了所得样品的晶体结构与电化学性能,研究了两种方法所制备的富锂锰基正极材料的结构、形貌与电化学性能。结果表明,一步草酸共沉淀法合成的富锂材料,拥有更好的结晶性、更大的层间距;材料的颗粒更为均匀和细小。这些晶体结构与形貌上的优势,使得该法制备的富锂材料展现出了更高的放电比容量、更好的循环性能和倍率性能。这些结果均展示了我们所提出的一步草酸共沉淀法的可行性与优势。这种新颖而简便的共沉淀法,可推广于其他层状材料的合成与设计。
For the first time, a novel method for synthesizing lithium-rich manganese-based cathode materials by one-step oxalic acid coprecipitation method based on ethanol was reported. In this method, all the elements including the lithium element can undergo a precipitation reaction at the coprecipitation reaction step, thereby achieving a more uniform mixing of the elements. In addition, compared with the traditional ammonium oxalate coprecipitation method, the method omits the step of initial calcination of the precursor and saves the time and cost of the synthesis. The crystal structure and electrochemical performance of the obtained samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and electrochemical measurements. The structures of the lithium-rich manganese-based cathode materials prepared by the two methods were studied. Morphology and electrochemical properties. The results show that the one-step oxalate coprecipitation synthesis of lithium-rich materials, with better crystallinity, greater layer spacing; material particles are more uniform and small. These crystal structures and morphological advantages, making the method of lithium-rich materials exhibit higher specific discharge capacity, better cycle performance and rate performance. These results demonstrate the feasibility and advantages of our proposed one-step oxalate coprecipitation method. This novel and simple coprecipitation method can be extended to the synthesis and design of other layered materials.