Liu Liang, Dai Wei, Zhu Hongzheng, Gu Yanguang, Wang Kangkang, Li Chao, Pan Chaofeng, Zhou Min, Liu Jian
Automotive Engineering Research Institute, Jiangsu University, Zhenjiang 212013, China.
School of Engineering, Faculty of Applied Science, University of British Columbia, Kelowna, BC V1V 1V7, Canada.
Nanomaterials (Basel). 2021 Feb 25;11(3):569. doi: 10.3390/nano11030569.
Silver vanadates (SVOs) have been widely investigated as cathode materials for high-performance lithium-ion batteries (LIBs). However, similar to most vanadium-based materials, SVOs suffer from structural collapse/amorphization and vanadium dissolution from the electrode into the electrolyte during the Li insertion and extraction process, causing poor electrochemical performance in LIBs. We employ ultrathin AlO coatings to modify β-AgVO (as a typical example of SVOs) by an atomic layer deposition (ALD) technique. The galvanostatic charge-discharge test reveals that ALD AlO coatings with different thicknesses greatly affected the cycling performance. Especially, the β-AgVO electrode with ~10 nm AlO coating (100 ALD cycles) exhibits a high specific capacity of 271 mAh g, and capacity retention is 31%, much higher than the uncoated one of 10% after 100 cycles. The Coulombic efficiency is improved from 89.8% for the pristine β-AgVO to 98.2% for AlO-coated one. Postcycling analysis by cyclic voltammetry (CV), cyclic voltammetry (EIS), and scanning electron microscopy (SEM) disclose that 10-nm AlO coating greatly reduces cathode-electrolyte interphase (CEI) resistance and the charge transfer resistance in the β-AgVO electrode. AlO coating by the ALD method is a promising technique to construct artificial CEI and stabilize the structure of SVOs, providing new insights for vanadium-based electrodes and their energy storage devices.
钒酸银（SVOs）作为高性能锂离子电池（LIBs）的阴极材料已被广泛研究。然而，与大多数钒基材料类似，在锂嵌入和脱出过程中，SVOs会出现结构坍塌/非晶化以及钒从电极溶解到电解液中的情况，导致LIBs的电化学性能不佳。我们采用原子层沉积（ALD）技术，用超薄AlO涂层对β-AgVO（作为SVOs的一个典型例子）进行改性。恒电流充放电测试表明，不同厚度的ALD AlO涂层对循环性能有很大影响。特别是，具有约10 nm AlO涂层（100个ALD循环）的β-AgVO电极表现出271 mAh g的高比容量，容量保持率为31%，远高于未涂层电极在100次循环后的10%。库仑效率从原始β-AgVO的89.8%提高到AlO涂层电极的98.2%。通过循环伏安法（CV）、循环伏安法（EIS）和扫描电子显微镜（SEM）进行的循环后分析表明，10 nm的AlO涂层大大降低了β-AgVO电极中的阴极-电解液界面（CEI）电阻和电荷转移电阻。通过ALD方法进行AlO涂层是构建人工CEI并稳定SVOs结构的一种有前途的技术，为钒基电极及其储能装置提供了新的见解。
