Liu Shiqi, Wan Jie, Wang Boya, Li Chenghan, Wang Yulong, Wang Lin, Wu Haipeng, Zhang Nian, Zhang Xu, Yu Haijun
Institute of Advanced Battery Materials and Devices, College of Materials Science and Engineering, Beijing University of Technology, Beijing, 100124, P. R. China.
Key Laboratory of Advanced Functional Materials, Ministry of Education, Beijing University of Technology, Beijing, 100124, P. R. China.
Small. 2024 Sep;20(36):e2401497. doi: 10.1002/smll.202401497. Epub 2024 May 1.
Manganese-based lithium-rich layered oxides (Mn-LLOs) are promising candidate cathode materials for lithium-ion batteries, however, the severe voltage decay during cycling is the most concern for their practical applications. Herein, an Mn-based composite nanostructure constructed LiMnO (LMO@LiMnO) is developed via an ultrathin amorphous functional oxide LiMnO coating at the grain surface. Due to the thin and universal LMO amorphous surface layer etched from the lithiation process by the high-concentration alkaline solution, the structural and interfacial stability of LiMnO are enhanced apparently, showing the significantly improved voltage maintenance, cycle stability, and energy density. In particular, the LMO@LiMnO cathode exhibits zero voltage decay over 200 cycles. Combining with ex situ spectroscopic and microscopic techniques, the Mn coexisted behavior of the amorphous LMO is revealed, which enables the stable electrochemistry of LiMnO. This work provides new possible routes for suppressing the voltage decay of Mn-LLOs by modifying with the composite functional unit construction.
锰基富锂层状氧化物（Mn-LLOs）是锂离子电池很有前景的候选正极材料，然而，循环过程中严重的电压衰减是其实际应用中最令人担忧的问题。在此，通过在晶粒表面涂覆超薄非晶态功能氧化物LiMnO构建了一种Mn基复合纳米结构LiMnO（LMO@LiMnO）。由于高浓度碱性溶液在锂化过程中蚀刻出的薄且普遍存在的LMO非晶表面层，LiMnO的结构和界面稳定性明显增强，显示出显著改善的电压保持率、循环稳定性和能量密度。特别是，LMO@LiMnO正极在200次循环中表现出零电压衰减。结合非原位光谱和显微镜技术，揭示了非晶LMO中Mn的共存行为，这使得LiMnO具有稳定的电化学性能。这项工作为通过复合功能单元构建改性来抑制Mn-LLOs的电压衰减提供了新的可能途径。
