Wang Zhihong, Wei Wu, Zhang Tao, Yu Haifeng, Li Chunzhong, Chen Ling, Jiang Hao
Shanghai Engineering Research Center of Hierarchical Nanomaterials, School of Materials Science and Engineering, East China University of Science and Technology, Shanghai, 200237, China.
State Key Lab of High Performance Ceramics and Superfine Microstructure, Shanghai Institute of Ceramics, Chinese Academy of Sciences, Shanghai, 200050, China.
Small. 2024 Jan;20(4):e2306160. doi: 10.1002/smll.202306160. Epub 2023 Sep 15.
The energy density of Ni-rich cathodes is expected to be further unlocked by increasing the cut-off voltage to above 4.3 V, which nevertheless come with significantly increased irreversible phase transition and abundant side reactions. In this study, the perovskite oxides enhanced radial-aligned LiNi Co Mn O (NCM811) cathodes are reported, in which the coherent-growth La [LiTM]O clusters are evenly riveted into the crystals and the stable La Ca [TM]O protective layer is concurrently formed on the surface. The reciprocal interactions greatly reduce the lattice strain during de-/lithiation. Meantime, the abundant oxygen vacancies of the coating layer are proved to reversibly capture (state of charge) and re-release (state of discharge) the oxygen radicals, fully avoiding their correlative side reactions. The resultant NCM811 displays negligible O and CO emissions when charging to 4.5 V as well as a thinner CEI film, therefore delivering a large capacity of 225 mAh g at 0.1C in coin-type half-cells and a high retention of 88.3% after 1000 cycles at 1C in pouch-type full-cells within 2.7-4.5 V. The development of high-voltage Ni-rich cathodes exhibits a highly effective pathway to further increase their energy density.
通过将截止电压提高到4.3V以上，有望进一步释放富镍阴极的能量密度，然而这会伴随着不可逆相变的显著增加和大量副反应。在本研究中，报道了钙钛矿氧化物增强的径向排列的锂镍钴锰氧化物（NCM811）阴极，其中相干生长的La[LiTM]O簇均匀地铆接在晶体中，并且在表面同时形成稳定的LaCa[TM]O保护层。相互作用大大降低了脱锂/锂化过程中的晶格应变。同时，证明了涂层中丰富的氧空位可逆地捕获（充电状态）和重新释放（放电状态）氧自由基，完全避免了它们相关的副反应。所得的NCM811在充电至4.5V时显示出可忽略不计的O和CO排放以及更薄的CEI膜，因此在硬币型半电池中以0.1C提供225 mAh g的大容量，并且在软包型全电池中在2.7-4.5V范围内以1C循环1000次后具有88.3%的高保持率。高压富镍阴极的开发展示了进一步提高其能量密度的高效途径。
