α-MnO_(2)作为先进的双功能ORR/IOR电催化剂构建可充电锌空电池  

α-MnO_(2) as an advanced bifunctional ORR/IOR electrocatalyst for Zn-air battery

作　　者：王振 赵慧 周菊红 盛可发 王涛 江彬彬 WANG Zhen;ZHAO Hui;ZHOU Juhong;SHENG Kefa;WANG Tao;JIANG Binbin(Anhui Key Laboratory of Photoelectric-Magnetic Functional Materials,School of Chemistry and Chemical Engineering,Anqing Normal University,Anqing 246011,China)

机构地区：[1]安庆师范大学化学化工学院光电磁材料安徽省重点实验室,安徽安庆246011

出　　处：《燃料化学学报（中英文）》2024年第2期266-276,共11页Journal of Fuel Chemistry and Technology

基　　金：安徽省自然科学基金(2008085QB53);安徽省教育厅高校科学研究重点项目(KJ2021A0642,KJ2021A0655);光电磁材料安徽省重点实验室开放基金(ZD2022004)资助。

摘　　要：析氧反应(oxygen evolution reaction,OER)和氧还原反应(oxygen reduction reaction,ORR)是可充电锌空电池(rechargeable Zn-air batteries,RZABs)重要的两个反应。其中,析氧反应具有较高的热力学平衡电位和复杂的反应路径,实际应用中需要高的充电电压驱动其发生,这将带来一系列问题并且限制了RZABs的商业化应用。基于此,本研究构造α-MnO_(2)并作为ORR/IOR双功能催化剂。在碱性体系中引入反应改性剂KI,α-MnO_(2)对碘离子氧化反应(iodide oxidation reaction,IOR)具有更低的阳极氧化电位和更快的催化动力学。当1.0 mol/L KOH电解液中添加0.5 mol/L KI时,相比于OER(1.709 V@10 mA/cm^(2)),α-MnO_(2)在IOR过程中电流密度达到10 mA/cm^(2)时阳极电位减小了398 mV(1.311 V vs.RHE),且表现出低至57.5 mV/dec塔菲尔斜率。相对于与Pt/C,在含有KI的KOH电解液中,α-MnO_(2)表现出与Pt/C相媲美的ORR活性。此外,以α-MnO_(2)为空气电极组装成RZAB后,该电池也表现出了优异的充电活性和良好的循环寿命,在5 mA/cm^(2)电流密度下,充放电电压间隙由0.97 V缩减为0.61 V,能量转换效率由54.9%提升至66.2%。Oxygen reduction reaction(ORR)and oxygen evolution reaction(OER)are important reactions for rechargeable Zinc-air batteries(RZABs).Unfortunatly,OER holds a high thermodynamic equilibrium potential and complex reaction path,which require an large votage to derive this reaction and greatly hinder its commercial application.Herein,α-MnO_(2) was successfully achieved and as the bifunctional ORR/iodide oxidation reaction(IOR)electrocatalyst.In alkline media,α-MnO_(2) exhibits fast kinetics and low oxidation potential for IOR.Expectedly,α-MnO_(2) exhibits remarkable IOR activity in 1.0 mol/L KOH with 0.5 mol/L KI.Compared with potential at 10 mA/cm^(2) for OER(1.709 V vs.RHE),the potential at 10 mA/cm^(2) reduce 398 mV(1.311 V vs.RHE)forα-MnO_(2) during IOR process.α-MnO_(2) also provides small Tafel slope of 57.5 mV/dec.Additionly,α-MnO_(2) represents outsanding ORR performances with respect to Pt/C.As an air electrode for RZAB,the fabricated RZAB delivers excellent performances.To be specific,at 5 mA/cm^(2),the voltage gap between charging and discharging reduces from 0.97 V to 0.61 V,energy efficiency increses from 54.9%to 66.2%.This work provide an unique strategy to construct bifunction ORR/IOR electrocatalysts and promote the commercialization of RZABs.

关 键 词：可充电锌空电池 析氧反应 碘离子氧化反应 α-MnO_(2) 

分 类 号：O643.36[理学—物理化学]