石墨烯/NG-S2復(fù)合材料，用于鋅-空氣電池

1成果簡介

開發(fā)高效穩(wěn)定的雙功能催化劑對推進(jìn)鋅空氣電池（ZABs）的大規(guī)模應(yīng)用至關(guān)重要。本文，安徽工業(yè)大學(xué)Shilei Ding等研究人員在《Electrochimica Acta》期刊發(fā)表名為“Secondary Sulfidation-Engineered Co/N–Graphene Catalyst for Boosted ORR/OER Bifunctionality in Zinc–Air Batteries”的論文，研究通過兩步硫化策略，合成了以氮摻雜石墨烯為載體的鈷基硫化物復(fù)合催化劑（Co@NG-S2）。

首階段硫化處理成功實現(xiàn)硫（S）與氮（N）的共摻雜，同時提升了石墨烯載體的導(dǎo)電性和活性。第二階段硫化促進(jìn)了鈷基硫化物的均勻分布，并增強(qiáng)了其與石墨烯的界面耦合，從而顯著提升了雙功能催化性能。電化學(xué)表征顯示，Co@NG-S2在紅外電極上呈現(xiàn)出0.868 V的氧還原反應(yīng)（ORR）起始電位和0.798 V的半波電位（E1/2）。對于氧析出反應(yīng)（OER），Co@NG-S2在10 mA cm-2電流密度下僅表現(xiàn)出430 mV的低過電位，展現(xiàn)出卓越的ORR/OER雙功能活性。此外，采用該催化劑組裝的液態(tài)ZAB實現(xiàn)了110 mW cm-2的峰值功率密度，并展現(xiàn)出超過200小時的循環(huán)穩(wěn)定性。本研究提出了一種合成高性能過渡金屬硫化物-碳基催化劑的新策略，為未來應(yīng)用展現(xiàn)出巨大潛力。

2圖文導(dǎo)讀

圖1. (a) Schematic diagram illustrating the synthesis process of the Co@NG-S2 catalyst. (b) Scanning electron microscopy (SEM) image of graphene. (c) SEM image of Co@NG. (d) SEM image of Co@NG-S1. (e-i) SEM image of Co@NG-S2 and its corresponding energy-dispersive X-ray spectroscopy (EDS) elemental mapping images. (j) Transmission electron microscopy (TEM) image of Co@NG-S2. (k, l) High-resolution transmission electron microscopy (HRTEM) images of Co@NG-S2.

圖2. (a) Raman spectra of Co@NG, Co@NG-S1, and Co@NG-S2. (b) XRD patterns of Co@NG, Co@NG-S1, and Co@NG-S2. (c) XPS survey spectra, (d) High-resolution XPS spectra of Co 2p orbitals, (e) Deconvoluted high-resolution XPS spectra of Co 2p orbitals, (f) High-resolution XPS spectra of N 1s orbitals, (g) High-resolution XPS spectra of C 1s orbitals for Co@NG-S2, Co@NG-S1, and Co@NG. (h) High-resolution XPS spectra of S 2p orbitals for Co@NG-S2 and Co@NG-S1.

圖3. Electrochemical performance of catalysts in 0.1 M KOH:(a) CV profiles of Co@NG-S2, Co@NG-S1, Co@NG, and Pt/C in O2-saturated and N2-saturated solutions, (b) ORR polarization curves at 1600 rpm, (c) Half-wave potentials and limiting current densities, (d) Tafel slopes derived from ORR polarization data. (e) OER polarization curves of Co@NG-S2, Co@NG-S1, Co@NG, and RuO2 catalysts. (f) Tafel slopes derived from OER polarization data. (g) Cdl of the samples. (h) ΔE values.

圖4. Schematic Illustration of the Enhanced OER and ORR Mechanism by Secondary Sulfurization Optimized Catalysts.

圖5. Rechargeable Zn-air battery assembled with Co@NG-S2 and Pt/C?+?RuO2: (a) Schematic diagram of the battery structure. (b) Open-circuit voltage. (c) Charge-discharge polarization curves. (d) Power density curves. (e) Partial view of constant-current charge-discharge cycling. (f) Photograph of an LED lit by the Co@NG-S2-based battery. (g) Long-term constant-current charge-discharge cycling profile.

3小結(jié)

本研究通過二次硫化法成功開發(fā)出一種由氮摻雜石墨烯負(fù)載的鈷基硫化物組成的獨立復(fù)合催化劑（Co@NG-S2）。該催化劑應(yīng)用于鋅空氣電池（ZABs）時，對氧還原反應(yīng)（ORR）和氧析出反應(yīng)（OER）均展現(xiàn)出卓越的雙功能催化活性。實驗表征表明，該催化劑在0.1M KOH溶液中展現(xiàn)出高ORR活性，起始電位為0.868V，半波電位為0.798V（相對于還原氧化電極），表明其具有高效的四電子轉(zhuǎn)移路徑。在1.0M KOH溶液中的氧析出反應(yīng)中，該催化劑表現(xiàn)卓越：于10mA cm?2電流密度下僅產(chǎn)生430 mV過電位，塔菲爾斜率達(dá)213.62mV dec?1，彰顯出快速反應(yīng)動力學(xué)特性。此外，當(dāng)集成于鋅空氣電池時，基于Co@NG-S2的空氣陰極實現(xiàn)了高達(dá)110 mW cm-2的峰值功率密度，并展現(xiàn)出卓越的長期循環(huán)穩(wěn)定性（超過200小時），超越了基準(zhǔn)Pt/C+RuO2催化劑體系。本研究提出了一種新型高性能過渡金屬硫化物-碳復(fù)合催化劑的工程化策略，為推進(jìn)鋅空氣電池的實際應(yīng)用提供了重要潛力。

文獻(xiàn)：
https://doi.org/10.1016/j.electacta.2025.147607

來源：材料分析與應(yīng)用