Efficient and stable electrocatalysts for oxygen reduction reaction and freestanding electrode structure were developed to reduce the use of polymer binders in the cathode of metal–air batteries. Considering the unique geometrical configurations of helical carbon nanotubes (CNTs) and improved properties compared with straight CNTs, we prepared high-purity [email protected]_x/helical nitrogen-doped carbon nanotubes ([email protected]_x/HNCNTs) on a carbon fiber paper by hydrothermal and single-step in situ chemical vapor deposition strategies. Under an optimized growth time (1 h), the synthesized [email protected]_x/HNCNTs provide richer edge defects and active sites and show prominent electrocatalytic performance toward oxygen reduction reaction (ORR) under alkaline media compared with [email protected]_x/HNCNTs-0.5 h and [email protected]_x/HNCNTs-2 h. The soft X-ray absorption spectroscopy technique is used to investigate the influences of different growth times on the electronic structure and local chemical configuration of [email protected]_x/HNCNTs. Furthermore, the Al–air coin cell employing [email protected]_x/HNCNTs-1 h as the binder-free cathode exhibits an open-circuit voltage of 1.48 V, a specific capacity of 367.31 mA h g^–1 at the discharge current density of 1.0 mA cm^–2, and a maximum power density (P_max) of 3.86 mW cm^–2, which are superior to those of [email protected]_x/HNCNTs-0.5 h and [email protected]_x/HNCNTs-2 h electrodes. This work provides valuable insights into the development of scalable binder-free cathodes, exploiting HNCNT composite materials with an outstanding electrocatalytic performance for ORR in Al–air systems.

中文翻译：

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可控合成[受电子邮件保护的] _x /螺旋氮掺杂碳纳米管作为氧电池的无粘结剂阴极，可进行氧还原反应

开发了用于氧还原反应和独立式电极结构的高效稳定的电催化剂，以减少金属-空气电池阴极中聚合物粘合剂的使用。考虑到螺旋碳纳米管（CNTs）的独特几何构型和与直碳纳米管相比改进的性能，我们在碳纤维上制备了高纯度[受电子邮件保护] _x /氮掺杂螺旋碳纳米管（[受电子邮件保护] _x / HNCNTs）论文通过水热和单步原位化学气相沉积策略。在最佳生长时间（1小时）下，合成的[受电子邮件保护] _x/ HNCNT与[电子邮件保护] _x /HNCNTs-0.5 h和[电子邮件保护] _x / HNCNTs-2 h相比，在碱性介质下提供了更丰富的边缘缺陷和活性位点，并显示出对氧还原反应（ORR）的显着电催化性能。软X射线吸收光谱技术用于研究不同生长时间对[受电子邮件保护的] _x / HNCNTs的电子结构和局部化学构型的影响。此外，采用[受电子邮件保护] _x / HNCNTs-1 h作为无粘结剂阴极的铝制硬币电池表现出1.48 V的开路电压，在放电电流密度为^-1时的比容量为367.31 mA hg ^–1。 1.0 mA厘米^–2，最大功率密度（P _max）为3.86 mW cm ^-2，优于[受电子邮件保护] _x /HNCNTs-0.5 h和[受电子邮件保护] _x / HNCNTs-2 h电极的功率密度。这项工作为可伸缩的无粘结剂阴极的开发提供了宝贵的见识，它利用具有出色电催化性能的HNCNT复合材料对铝空气系统中的ORR进行了研究。