Crack-free single-crystalline Ni-rich layered NCM cathode enable superior cycling performance of lithium-ion batteries
Crack-free single-crystalline Ni-rich layered NCM cathode enable superior cycling performance of lithium-ion batteries
复制标题
无裂纹单晶富镍层状NCM正极可实现锂离子电池优异的循环性能
DOI：
10.1016/j.nanoen.2020.104450
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发表时间：
2020-04-01
期刊：
影响因子：
17.6
通讯作者：
Yang, Yong
中科院分区：
文献类型：
--
作者：
Fan, Xinming;Hu, Guorong;Yang, Yong
富镍层状氧化物由于其能量密度高、成本合理等优点，在锂离子电池正极材料中得到了广泛应用。然而，具有晶界的二次粒子的分层结构不可避免地会导致结构崩溃和严重的电极/电解质界面寄生反应，晶间裂纹是由各向异性收缩和膨胀引起的。本文研制并全面研究了初生颗粒直径为3 ~ 6 μ m的lini0.83 co0.11 mn0.060 o2 （SC-NCM）单晶材料，该材料在室温和高温（55℃）下均表现出优异的循环性能，且长期循环后结构完整性显著提高。值得注意的是，具有实际负载（8.7 mAh cm(-2)）的SiO-C平行于SC-NCM袋式全电池在45℃下以1C （1C = 200 mA g(-1)）的电流循环600次后，容量保持率为84.8%，保持225 Wh/kg的高比能密度。结合x射线光电子能谱、飞行时间二次离子质谱和扫描透射电镜，我们发现微米尺寸的SC-NCM颗粒有效地减轻了不希望的电极/电解质侧相互作用，防止了晶间裂纹的产生，从而减轻了不可逆的结构降解。开发单晶微米级颗粒的策略为维持富镍层状NCM阴极在高温下的结构稳定性和提高循环寿命提供了新的途径。
Ni-rich layered oxides are extensively employed as a promising cathode material in lithium ion batteries (LIBs) due to their high energy density and reasonable cost. However, the hierarchical structure of secondary particles with grain boundaries inevitably induces the structural collapse and severe electrode/electrolyte interface parasitic reactions as the intergranular crack arises from the anisotropic shrink and expansion. Herein, the single-crystalline LiNi0.83Co0.11Mn0.06O2 (SC-NCM) with primary particles of 3-6 mu m diameter is developed and comprehensively investigated, which exhibits superior cycling performance at both room temperature and elevated temperature (55 degrees C) as well as significantly improved structural integrity after long-term cycling. Remarkably, the SiO-C parallel to SC-NCM pouch-type full cell with a practical loading (8.7 mAh cm(-2)) delivers a capacity retention of 84.8 % at 45 degrees C after 600 cycles at a current rate of 1C (1C = 200 mA g(-1)), retaining a high specific energy density of 225 Wh/kg. Using a combination of X-ray photoelectron spectroscopy, time-of-flight secondary-ion mass spectrometry and scanning transmission electron microscopy, we reveal that SC-NCM particles with micron-sizes effectively mitigate the undesired electrode/electrolyte side interactions and prevent the generation of intergranular cracks, thereby alleviating irreversible structural degradation. The strategy of developing single-crystalline micron-sized particles may offer a new path for maintaining the structural stability and improving cycling life of Ni-rich layered NCM cathodes even under high temperature.