在碳气凝胶中构建五边形拓扑缺陷，用于柔性锌空气电池

摘要：在能量转换方面，设计和合成用于氧还原反应（ORR）的高性能无金属碳电催化剂至关重要。本文，华南理工大学彭新文教授团队在《Small》期刊发表名为“Constructing Pentagonal Topological Defects in Carbon Ae

1成果简介

在能量转换方面，设计和合成用于氧还原反应（ORR）的高性能无金属碳电催化剂至关重要。本文，华南理工大学彭新文教授团队在《Small》期刊发表名为“Constructing Pentagonal Topological Defects in Carbon Aerogels for Flexible Zinc-Air Batteries”的论文，研究提出了一种一步法掺氮/萃取策略，以制备具有丰富五边形碳拓扑缺陷的三维掺氮碳气凝胶（NCA-Cl）。在碱性（0.1 m KOH）和酸性（0.1 m HClO4）介质中，NCA-Cl 电催化剂表现出极佳的 ORR 活性，半波电位分别为 0.89 V vs RHE 和 0.74 V vs RHE。配备了 NCA-Cl 阴极的水性锌-空气电池（ZAB）的峰值功率密度为 206.6 mW cm*-2，比容量为 810.6 mAh g-1，耐用时间为 400 h，柔性 ZAB 的性能也令人信服。这项工作为形成拓扑碳缺陷以提高碳基催化剂的电催化活性提供了一种有效的策略。

2图文导读

图1、Schematic of the microstructure and possible pyrolysis process of NCA-Cl. a) Scheme of possible formation processes of carbon defects. b) Micro-CT image of NCA-Cl. c) SEM images of NCA-Cl. d) ACTEM image of NCA-Cl after FFT. e) XRD patterns, Raman spectra f), and EPR spectra g) of CA, CA-Cl, NCA, and NCA-Cl samples. XPS spectra h), Nitrogen content and relative content of each N-specie i), and ICP-OES j) of CA, CA-Cl, NCA, and NCA-Cl.

图2、Mechanism of formation of pentagonal defects in NCA-Cl. The XRD patterns a), IR spectra b), and configurations of N dopants c) of NCA-Cl at different temperatures. TG-IR-MS analysis d–f) of gases evolved from the thermal degradation of NCA-Cl. TG-MS analysis g) of gases evolved from the thermal degradation of NCA. MS analysis h) of gases evolved from the thermal degradation of NCA and NCA-Cl. i) The high-resolution N 1s XPS spectra of NCA-Cl at different temperatures. j) Raman spectra of NCA-Cl at different temperatures. k) Schematic diagram of carbon defect formation.

图3、ORR and OER activity of NCA-Cl in 0.1 m KOH. a) LSV curves. b) Eonset, E1/2, and JL values. c)JK values. d) Tafel plots. e) LSV curves and corresponding K-L curves. f) Electron transfer number and H2O2 peroxide yield. g) The durability of the NCA-Cl catalyst and Pt/C for ORR. h) RDE polarization curves for OER. i) △E of samples for bifunctional electrocatalytic activity.

图4、ORR activity of NCA-Cl in 0.1 m HClO4. a) LSV patterns. b) Eonset and E1/2 values. c)JK values. d) Tafel plots. e) Cdl values. f) LSV curves and corresponding K–L curves. g) Electron transfer number and H2O2 peroxide yield. h) The durability of the NCA-Cl catalyst for ORR. i) EIS plots and equivalent circuits.

图5、Electrochemical performances of the NCA-Cl-based aqueous and compressible flexible ZAB. a) Discharge curves of the NCA-Cl-based and Pt/C+RuO2 ZAB at various current densities. b) Specific discharge capacities at current densities of 5 and 10 mA cm−2. c) Power density curves of the rechargeable Zn-air batteries with NCA-Cl-based and Pt/C+RuO2. d) Charge–discharge cycle stability curve at 1.0 mA cm−2. e) Schematic illustration of a flexible ZAB using NCA-Cl as the air cathode. f) Discharge curves with current densities from 1 to 10 mA cm−2. g) Polarization and power density curves of the rechargeable flexible ZAB with NCA-Cl. h) Charge and discharge cycle tests at different folding angles at 1 mA cm−2.

图6、Density functional theory calculations. a) The projected density of states (PDOS) and b) Bader charges of C-565 and C-565-N structures. Calculated ORR free energy diagrams of c) C-565, and d) C-565-N. e) In situ FTIR spectra for NCA-Cl in 0.1 m KOH. f) The detailed variations of O*2 and OOH with potential. g) Optimized configurations of , OOH, O, and OH on NCA-Cl.

3小结

总之，采用一步热解法制备了具有丰富五边形缺陷的氮掺杂碳气凝胶电催化剂（NCA-Cl），用于柔性锌-空气电池。在热解过程中，氮原子经历了捕获和碰撞连根拔起的动态过程，促使不饱和碳原子发生碳重排，形成五边形缺陷。这种一体式电催化剂具有独特的电子结构，在碱性介质（E1/2 = 0.89 V vs RHE at 0.1 m KOH）和酸性介质（E1/2 = 0.74 V vs RHE at 0.1 m HClO4）中均表现出显著的电催化活性和稳定性。理论计算表明，NCA-Cl 催化剂的高 ORR 性能是由于五边形缺陷和氮掺杂剂之间的协同效应，它们共同调节了碳基底的几何和电子特性，确保了催化剂对 O2 的高亲和力以及对关键 OOH 中间体的适当吸附/解吸能力。将 NCA-Cl 用作锌水电池的阴极催化剂时，其峰值功率密度为 206.6 mW cm*-2，比容量为 810.6 mAh g-1，并在 1 mA cm-2 的电流密度下稳定工作了 400 多小时。此外，用基于 NCA-Cl 的催化剂组装的柔性锌-空气电池也表现出了卓越的性能。这项工作不仅极大地推动了我们对拓扑碳缺陷起源的认识，而且为纳米碳中定向拓扑缺陷的可控合成提供了一种有效的方法。

文献
:https://doi.org/10.1002/smll.202502067