Department of Chemistry, Tsinghua University, Beijing 100084, People's Republic of China.
Nanoscale. 2014 Oct 7;6(19):11419-24. doi: 10.1039/c4nr02576h.
Atomic layer deposition (ALD) was applied to deposit ZnO on graphene aerogel, and this composite was used as an anode material for lithium ion batteries. This electrode material was further modified by an ultrathin Al2O3 layer via ALD to stabilize its electrochemical stability. These two metal oxides were uniformly immobilized on graphene frameworks, and the Al2O3 coating strongly improved the electrochemical performances of ZnO-graphene aerogel composite anodes. Particularly, the composite with 10 ALD cycles of Al2O3 coating (denoted as ZnO-G-10) exhibited a high initial discharge capacity of 1513 mA h g(-1) and maintained a reversible capacity of 490 mA h g(-1) after 100 cycles at a current density of 100 mA g(-1). Furthermore, the capacity retention rate increased from 70% to 90% in comparison with its uncoated counterpart after 100 cycles. The ZnO-G-10 anode also showed good rate-capability, delivering a discharge capacity of 415 mA h g(-1) at 1000 mA g(-1). The improved electrochemical performance is attributed to the formation of an artificial solid electrolyte interphase layer, stabilizing ZnO and the electrolyte by preventing the aggregation of Zn/ZnO nanograins and the side reaction that would cause the degradation of anodes.
原子层沉积（ALD）被应用于在石墨烯气凝胶上沉积 ZnO，并且该复合材料被用作锂离子电池的阳极材料。通过 ALD，进一步通过超薄 Al2O3 层对该电极材料进行修饰，以稳定其电化学稳定性。这两种金属氧化物均匀地固定在石墨烯框架上，Al2O3 涂层强烈地改善了 ZnO-石墨烯气凝胶复合阳极的电化学性能。特别地，具有 10 次 ALD 循环的 Al2O3 涂层的复合材料（表示为 ZnO-G-10）表现出 1513 mA h g-1 的初始放电容量，并且在 100 mA g-1 的电流密度下经过 100 次循环后保持 490 mA h g-1 的可逆容量。此外，与未涂层的对应物相比，在 100 次循环后，其容量保持率从 70%增加到 90%。ZnO-G-10 阳极在 1000 mA g-1 时还表现出良好的倍率性能，可提供 415 mA h g-1 的放电容量。电化学性能的提高归因于形成了人工固体电解质界面层，通过阻止 Zn/ZnO 纳米颗粒的聚集和导致阳极降解的副反应，稳定了 ZnO 和电解质。
