State Key Laboratory for Modification of Chemical Fibers and Polymer Materials ; Donghua University , Shanghai 201620 , China.
Department of Materials Science and Engineering , Southern University of Science and Technology , Shenzhen 518000 , China.
ACS Appl Mater Interfaces. 2018 Sep 5;10(35):29448-29456. doi: 10.1021/acsami.8b07863. Epub 2018 Aug 22.
Metal-free bifunctional oxygen electrocatalysts are extremely critical to the advanced energy conversion devices, such as high energy metal-air batteries. Effective tuning of edge defects and electronic density on carbon materials via simple methods is especially attractive. In this work, a facile alkali activation method has been proposed to prepare carbon with large specific surface area and optimized porosity. In addition, subsequent nitrogen-doping leads to high pyridinic-N and graphitic-N contents and abundant edge defects, further enhancing electrochemical activities. Theoretical modeling via first-principles calculations has been conducted to correlate the electrocatalytic activities with their fundamental chemical structure of N doping and edge defect engineering. The metal-free product (NKCNPs-900) shows a high half-wave potential of 0.79 V (ORR). Furthermore, the assembled Zn-air batteries display excellent performance among carbon-based metal-free oxygen electrocatalysts, such as large peak power density up to 131.4 mW cm, energy density as high as 889.0 W h kg at 4.5 mA cm, and remarkable discharge-charge cycles up to 575 times. Preliminarily, the rechargeable nonaqueous Li-air batteries were also investigated. Therefore, our work provides a low-cost, metal-free, and high-performance bifunctional carbon-based electrocatalyst for metal-air batteries.
无金属双功能氧电催化剂对于先进的能量转换设备（如高能金属-空气电池）至关重要。通过简单的方法有效调节碳材料的边缘缺陷和电子密度特别具有吸引力。在这项工作中，提出了一种简便的碱活化方法来制备具有大比表面积和优化孔隙率的碳。此外，随后的氮掺杂导致高吡啶-N 和石墨-N 含量和丰富的边缘缺陷，进一步增强了电化学活性。通过第一性原理计算进行理论建模，将电催化活性与其 N 掺杂和边缘缺陷工程的基本化学结构相关联。无金属产物（NKCNPs-900）表现出 0.79 V（ORR）的高半波电位。此外，组装的锌空气电池在基于碳的无金属氧电催化剂中表现出优异的性能，例如高达 131.4 mW cm 的峰值功率密度、4.5 mA cm 时高达 889.0 W h kg 的能量密度以及高达 575 次的出色充放电循环。初步研究了可再充电非水电锂空气电池。因此，我们的工作为金属-空气电池提供了一种低成本、无金属和高性能的双功能碳基电催化剂。
