Direct Fabrication of Lithium Double Oxides Films by Solution Processes

LiCoO_2、LiNiO_2等锂硫双金属氧化物是目前研究最多的锂电池正极材料。采用溶胶-凝胶法、喷雾热解法、化学气相沉积法和化学气相沉积法在真空中制备了包括溅射和激光烧蚀在内的薄膜。这些方法会消耗大量的能量，比如在800℃的温度下加热/烧制，产生高能物种，和/或保持真空。为了最大限度地减少能源和材料的消耗，我们提出了软溶液工艺来制备像双氧锂这样的高功能陶瓷薄膜。在本研究中，我们成功地在RT-200℃的低温水溶液中直接制备了LiCoO_2和/或LiNiO_2薄膜，而不需要进行任何后续烧成。所开发的水热/电化学方法使我们能够在铂、镍、石墨上以及在钴衬底上制备这些薄膜。它们结晶良好，具有电化学活性。我们还可以展示一种可能的在任何衬底上直接形成陶瓷膜的图案，包括纸/布/聚合物等有机多孔材料。

Lithiuun double oxides like LiCoO_2, LiNiO_2, etc. are most extensively studied for electrode materials for lithium batteries. Their films have been fabricated by sol-gel, spray-pyrolysis, CVD and PVD including sputtering and laser ablation methods in vacuum. Those methods would consume huge amount of energies by heating/firing at >800 ℃, creating highly energetic species, and/or keeping vacuum. To minimize the consumption of energies and materials, we are proposing "Soft Solution Processing" to fabricate highly functional ceramics film like lithium double oxides.In the present study, we have succeeded to fabricate the films of LiCoO_2 and/or LiNiO_2 directly in aqueous solutions at low temperatures at RT-200℃ without any post-firing. The developed hydrothermal/electrochemical methods enable us to fabricate those films on Pt, Ni, Graphite, as well as Ni on Co substrates. They are well-crystallized and electrochemically active. We could also demonstrate a possible a possible direct patterning of ceramic films on any substrate including organic porous materials like paper/cloth/polymers.