Deformation-tolerant metal anodes for flexible sodium–air fiber batteries
Lei Ye, Xiangran Cheng, Meng Liao, Tiancheng Zhao, Xinlin Huang, Xinyue Kang, Kun Zhang, Xuemei Sun, Bingjie Wang, Huisheng Peng
Abstract
Although flexible sodium–air (Na–air) batteries with high theoretical energy density offer promising opportunities for next-generation smart electronics, enhancing the safety and efficiency of flexible sodium metal anodes under dynamic and continuous deformation remains a challenge. Here, a flexible sodiated carbon nanotube layer to suppress dendrite growth under various deformations is demonstrated through a Fermi level-driven spontaneous synthetic process. The resulting sodiated carbon nanotube layer, which has a spontaneously formed solid–electrolyte interface and a robust interlocked structure, creates a uniformly distributed electric field and stable interface even under deformation, affording dendrite-free flexible Na metal anodes. With this deformation-tolerant Na metal anode, we have constructed a new family of highly flexible Na–air fiber batteries with excellent cycling performance for 400 cycles at a current density of 1000 mA·g−1 and a capacity limit of 500 mAh·g−1 under dynamic deformation. These Na–air fiber batteries can be further woven into self-powering systems to support flexible electronic devices.