Xia Xianming, Lv Xiang, Yao Yu, Chen Dong, Tang Fang, Liu Lin, Feng Yuezhan, Rui Xianhong, Yu Yan
School of Materials and Energy, Guangdong University of Technology, Guangzhou 510006, China.
Hefei National Laboratory for Physical Sciences at the Microscale, Department of Materials Science and Engineering, Key Laboratory of Materials for Energy Conversion, Chinese Academy of Sciences (CAS), University of Science and Technology of China, Hefei, Anhui 230026, China.
Nanoscale Horiz. 2022 Jul 25;7(8):899-907. doi: 10.1039/d2nh00152g.
Sodium (Na) metal is a very encouraging anode material for next-generation rechargeable batteries owing to its high specific capacity, earth-abundance and low-cost. However, the application of Na metal anodes (SMAs) is hampered by dendrite growth and "dead" Na formation caused by the uncontrollable Na deposition, leading to poor cycle life and even safety concerns. Herein, a high-performance Na anode is designed by introducing an artificial VN interlayer on the Na metal surface (Na/VN) by a simple mechanical rolling process to regulate Na nucleation/deposition behaviors. The density functional theory (DFT) and experiment results uncover that the VN possesses high "sodiophilicity", which can facilitate the initially homogeneous Na nucleation and cause Na to distribute evenly on the VN interlayer. Therefore, uniform Na deposition with dendrite-free morphology and prolonged cycling lifespan (over 1060 h at 0.5 mA cm/1 mA h cm) can be realized. Moreover, the full cell assembled by coupling a NaV(PO) (NVP) cathode and Na/VN anode presents superior cycling performance (, 96% capacity retention even after 800 cycles at 5C). This work provides a promising direction for regulating Na nucleation and deposition to achieve dendrite-free metal anodes.
钠（Na）金属因其高比容量、地壳丰度高和成本低，是下一代可充电电池非常有前景的阳极材料。然而，钠金属阳极（SMA）的应用受到枝晶生长和由不可控的钠沉积导致的“死”钠形成的阻碍，从而导致循环寿命短，甚至存在安全隐患。在此，通过简单的机械轧制工艺在钠金属表面引入人工VN中间层（Na/VN）来设计高性能钠阳极，以调节钠的成核/沉积行为。密度泛函理论（DFT）和实验结果表明，VN具有高“亲钠性”，这可以促进初始均匀的钠成核，并使钠均匀分布在VN中间层上。因此，可以实现无枝晶形态的均匀钠沉积和延长的循环寿命（在0.5 mA cm/1 mA h cm下超过1060小时）。此外，由NaV(PO)（NVP）阴极和Na/VN阳极耦合组装的全电池具有优异的循环性能（即使在5C下800次循环后，容量保持率仍为96%）。这项工作为调节钠的成核和沉积以实现无枝晶金属阳极提供了一个有前景的方向。
