Department of Mechanical and Materials Engineering, University of Western Ontario, London, Ontario, N6A 5B9, Canada.
Department of Physics and Astronomy, University of Western Ontario, London, Ontario, N6A 3K7, Canada.
Adv Mater. 2017 May;29(18). doi: 10.1002/adma.201606663. Epub 2017 Mar 3.
Na-metal batteries are considered as the promising alternative candidate for Li-ion battery beneficial from the wide availability and low cost of sodium, high theoretical specific capacity, and high energy density based on the plating/stripping processes and lowest electrochemical potential. For Na-metal batteries, the crucial problem on metallic Na is one of the biggest challenges. Mossy or dendritic growth of Na occurs in the repetitive Na stripping/plating process with an unstable solid electrolyte interphase layer of nonuniform ionic flux, which can not only lead to the low Coulombic efficiency, but also can create short circuit risks, resulting in possible burning or explosion. In this communication, the atomic layer deposition of Al O coating is first demonstrated for the protection of metallic Na anode for Na-metal batteries. By protecting Na foil with ultrathin Al O layer, the dendrites and mossy Na formation have been effectively suppressed and lifetime has been significantly improved. Furthermore, the thickness of protective layer has been further optimized with 25 cycles of Al O layer presenting the best performance over 500 cycles. The novel design of atomic layer deposition protected metal Na anode may bring in new opportunities to the realization of the next-generation high energy-density Na metal batteries.
钠金属电池被认为是锂离子电池的有前途的替代品，因为钠的广泛可用性和低成本、高理论比容量、基于电镀/剥离过程的高能量密度以及最低的电化学势。对于钠金属电池，金属钠的关键问题是最大的挑战之一。在重复的 Na 剥离/电镀过程中，Na 会发生苔藓或枝晶生长，具有不均匀离子通量的不稳定固体电解质界面层，这不仅会导致低库仑效率，还会产生短路风险，从而导致可能的燃烧或爆炸。在本通讯中，首次展示了原子层沉积 Al O 涂层来保护钠金属电池的金属 Na 阳极。通过用超薄 Al O 层保护 Na 箔，可以有效抑制枝晶和苔藓状 Na 的形成，并显著提高寿命。此外，还进一步优化了保护层的厚度，具有 25 个循环的 Al O 层在 500 个循环以上表现出最佳性能。原子层沉积保护的金属 Na 阳极的新颖设计可能为实现下一代高能量密度 Na 金属电池带来新的机遇。
