Easily Obtaining Excellent Performance High‐voltage LiCoO2 via Pr6O11 Modification
Easily Obtaining Excellent Performance High‐voltage LiCoO2 via Pr6O11 Modification
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通过Pr6O11改性轻松获得性能优异的高压LiCoO2
DOI：
10.1002/eem2.12311
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发表时间：
2021
影响因子：
15
通讯作者：
Zhigao Huang
中科院分区：
文献类型：
--
作者：
Yongcong Huang;Chenjie Xu;Jingguo Gao;L. Shen;Qian Liu;Guiying Zhao;Qingshui Xie;Yingbin Lin;Jiaxin Li;Zhigao Huang
开发一种合成高性能高压钴酸锂（LiCoO₂）的有效方法对其在锂电池（LIBs）中的工业化至关重要。本研究首次提出一种简单的可大规模生产的策略，即通过液相混合结合退火的方法，将负温度系数热敏的Pr₆O₁₁纳米粒子均匀地修饰在LiCoO₂上，制备出LiCoO₂@Pr₆O₁₁（LCO@PrO）。在274 mA g⁻¹的电流下进行测试，改性后的LCO@PrO电极在25℃和60℃时展现出优异的4.5 V高压循环性能，容量保持率分别为90.8%和80.5%，远高于未改性的LCO电极的22.8%和63.2%。采用了几种有效的策略来清晰地揭示Pr₆O₁₁修饰所带来的性能增强机制。研究发现，Pr₆O₁₁可以提高界面相容性，在高温下表现出更好的导电性，从而增强Li⁺扩散动力学，并抑制LCO的相变及其产生的机械应力。450 mAh的LCO@PrO‖石墨软包电池表现出优异的LIB性能和更好的热安全特性。重要的是，这种软包电池在5C倍率下的能量密度甚至提高了约42%。这种极其便捷的技术对于生产高能量密度的LIBs且成本增加可忽略不计是可行的，无疑为工业化提供了重要的学术启示。
Developing an effective method to synthesize high‐performance high‐voltage LiCoO2 is essential for its industrialization in lithium batteries (LIBs). This work proposes a simple mass‐produced strategy for the first time, that is, negative temperature coefficient thermosensitive Pr6O11 nanoparticles are uniformly modified on LiCoO2 to prepare LiCoO2@Pr6O11 (LCO@PrO) via a liquid‐phase mixing combined with annealing method. Tested at 274 mA g−1, the modified LCO@PrO electrodes deliver excellent 4.5 V high‐voltage cycling performance with capacity retention ratios of 90.8% and 80.5% at 25 and 60 °C, being much larger than those of 22.8% and 63.2% for bare LCO electrodes. Several effective strategies were used to clearly unveil the performance enhancement mechanism induced by Pr6O11 modification. It is discovered that Pr6O11 can improve interface compatibility, exhibit improved conductivity at elevated temperature, thus enhance the Li+ diffusion kinetics, and suppress the phase transformation of LCO and its resulting mechanical stresses. The 450 mAh LCO@PrO‖graphite pouch cells show excellent LIB performance and improved thermal safety characteristics. Importantly, the energy density of such pouch cell was increased even by ~42% at 5 C. This extremely convenient technology is feasible for producing high‐energy density LIBs with negligible cost increase, undoubtedly providing important academic inspiration for industrialization.