可充锌空气电池非贵金属阴极催化剂研究进展

针对不同催化剂体系下可充锌空气电池的研究情况和发展问题进行了综述。可充锌空气电池的氧还原反应(ORR)和氧析出反应(OER)速度缓慢,限制了它们的大规模应用。目前对可充锌空气电池的研究主要集中在非贵金属阴极催化剂上,以杂原子掺杂碳材料、过渡金属氧化物以及过渡金属硫化物为代表。最后对非贵金属阴极催化剂研究提出了展望。

NiCo2O4/RGO催化剂的制备及用于锌-空气电池

通过水热反应制备镍钴氧化物/还原氧化石墨烯(NiCo2O4/RGO)电催化材料。采用XRD、SEM和X射线光电子能谱(XPS)等测试对制备的催化剂的形貌、成分和结构进行分析,该催化剂呈现出花状纳米针结构;采用旋转圆盘电极,线性扫描伏安(LSV)曲线对催化剂的氧还原反应(ORR)和析氧反应(OER)电催化活性进行研究。催化材料在6 mol/L KOH电解液中,具有0.81 V的半波电势、6.73 m A/cm2的极限扩散电流密度和67 m V/dec的Tafel斜率。应用于可充锌-空气电池中,NiCo2O4/RGO的功率密度为230 m W/cm2,且具有良好的充放电循环稳定性。

基于镍/氮掺杂碳复合材料的双功能电催化剂合成及电化学性能研究

通过高温热解氢氧化镍/聚苯胺前驱体,制备了镍/氮掺杂碳复合材料,并作为双功能电催化剂应用于可充电锌-空气电池。利用X射线衍射、透射电镜、拉曼光谱、X射线光电子能谱等对样品的形貌与结构进行表征,并利用电化学工作站与旋转圆盘电极对样品的氧还原与氧析出电催化性能进行测试。线性扫描伏安曲线的结果表明,在0.1 M KOH水溶液中氧还原起始电位与半波电位分别为0.894 V和0.833 V vs.RHE,接近商业Pt/C。氧析出过电位在电流密度为10 mA·cm^(-2)时为0.356 V vs.RHE,略优于RuO_(2)。

3D hierarchically macro-/mesoporous graphene frameworks enriched with pyridinic-nitrogen-cobalt active sites as efficient reversible oxygen electrocatalysts for rechargeable zinc-air batteries

Efficient and affordable electrocatalysts for reversible oxygen reduction and oxygen evolution reactions(ORR and OER,respectively)are highly sought-after for use in rechargeable metal-air batteries.However,the construction of high-performance electrocatalysts that possess both largely accessible active sites and superior ORR/OER intrinsic activities is challenging.Herein,we report the design and successful preparation of a 3D hierarchically porous graphene framework with interconnected interlayer macropores and in-plane mesopores,enriched with pyridinic-nitrogen-cobalt(pyri-N-Co)active sites,namely,CoFe/3D-NLG.The pyri-N-Co bonding significantly accelerates sluggish oxygen electrocatalysis kinetics,in turn substantially improving the intrinsic ORR/OER activities per active site,while copious interlayer macropores and in-plane mesopores enable ultra-efficient mass transfer throughout the graphene architecture,thus ensuring sufficient exposure of accessible pyri-N-Co active sites to the reagents.Such a robust catalyst structure endows CoFe/3D-NLG with a remarkably enhanced reversible oxygen electrocatalysis performance,with the ORR half-wave potential identical to that of the benchmark Pt/C catalyst,and OER activity far surpassing that of the noble-metal-based RuO2 catalyst.Moreover,when employed as an air electrode for a rechargeable Zn-air battery,CoFe/3D-NLG manifests an exceedingly high open-circuit voltage(1.56 V),high peak power density(213 mW cm^(–2)),ultra-low charge/discharge voltage(0.63 V),and excellent charge/discharge cycling stability,outperforming state-of-the-art noble-metal electrocatalysts.

A novel composite(FMC)to serve as a durable 3D-clam-shaped bifunctional cathode catalyst for both primary and rechargeable zinc-air batteries

Novel and highly durable air cathode electrocatalyst with three dimensional （3D）-clam-shaped structure, MnO2 nanotubes-supported Fe2O3 （Fe2O3/MnO2） composited by carbon nanotubes （CNTs） （（Fe2O3/ MnO2）3/4-（CNTs）1/4） is synthesized using a facile hydrothermal process and a following direct heat- treatment in the air. The morphology and composition of this catalyst are analyzed using scanning elec- tronic microscopy （SEM）, transmission electron microscopy （TEM）, X-ray diffraction （XRD） and energy dispersive X-ray spectroscopy （EDX）. The morphology characteristics reveal that flower-like Fe2O3 parti- cles are highly dispersed on both MnO2 nanotubes and CNT surfaces, coupling all three components firmly. Electrochemical measurements indicate that the synergy of catalyst exhibit superior bi- functional catalytic activity for both oxygen reduction reaction （ORR） and oxygen evolution reaction （OER） as well as stability than Pt/C and lrO2 catalysts. Using these catalysts for air-cathodes, both primary and rechargeable zinc-air batteries （ZABs） are assembled for performance validation. In a primary ZAB, this 3D-clamed catalyst shows a decent open circuit voltage （OCV, -1.48 V） and a high discharge peak power density （349 mW cm 2）, corresponding to a coulomhic efficiency of 92%. In a rechargeahle ZABs with this bifunctional catalyst, high OCV （〉1.3 V） and small charge-discharge voltage gap （〈1.1 V） are achieved along with high specific capacity （780 mAh g 1 at 30 mA cm-2） and robust cycle-life （1,390 cycles at cycle profile of 20 mA/10 min）.