Electronic and Defective Engineering of Electrospun CaMnO3 Nanotubes for Enhanced Oxygen Electrocatalysis in Rechargeable Zinc-Air Batteries
Electronic and Defective Engineering of Electrospun CaMnO3 Nanotubes for Enhanced Oxygen Electrocatalysis in Rechargeable Zinc-Air Batteries
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DOI：
10.1002/aenm.201800612
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发表时间：
2018-08-06
影响因子：
27.8
通讯作者：
Ramakrishna, Seeram
中科院分区：
文献类型：
--
作者：
Peng, Shengjie;Han, Xiaopeng;Ramakrishna, Seeram
合理设计和批量生产具有良好氧还原反应（ORR）和析氧反应（OER）活性的双功能催化剂对金属-空气电池和燃料电池的发展至关重要。本文通过静电纺丝技术、煅烧和硫化处理，实现了可控的大规模硫掺杂CaMnO3纳米管的合成。硫掺杂不仅可以取代氧原子提高本征电导率，还可以引入丰富的氧空位，提供足够的催化活性位点，这一点通过密度泛函理论计算得到了进一步的证明。所得的硫改性CaMnO3 （CMO/S）在碱性溶液中对ORR和OER表现出更好的电催化活性，且稳定性优于原始CMO。这些结果突出了硫处理作为提高原始CaMnO3的ORR和OER催化活性的一种简单而有效的策略的重要性。作为概念验证，使用双功能催化剂的可充电锌空气电池具有较小的充放电电压极化和较长的循环寿命。此外，固态柔性可充电锌空气电池具有优越的充放电性能和卓越的稳定性。因此，CMO/S纳米管可能是金属-空气电池和燃料电池中pt基电催化剂的有希望的替代品。
Rational design and massive production of bifunctional catalysts with superior oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) activities are essential for developing metal-air batteries and fuel cells. Herein, controllable large-scale synthesis of sulfur-doped CaMnO3 nanotubes is demonstrated via an electrospinning technique followed by calcination and sulfurization treatment. The sulfur doping can not only replace oxygen atoms to increase intrinsic electrical conductivity but also introduce abundant oxygen vacancies to provide enough catalytically active sites, which is further demonstrated by density functional theory calculation. The resulting sulfur-modified CaMnO3 (CMO/S) exhibits better electrocatalytic activity for ORR and OER in alkaline solution with higher stability performance than the pristine CMO. These results highlight the importance of sulfur treatment as a facile yet effective strategy to improve the ORR and OER catalytic activity of the pristine CaMnO3. As a proof-of-concept, a rechargeable Zn-air battery using the bifunctional catalyst exhibits a small charge-discharge voltage polarization, and long cycling life. Furthermore, a solid-state flexible and rechargeable Zn-air battery gives superior discharge-charge performance and remarkable stability. Therefore, the CMO/S nanotubes might be a promising replacement to the Pt-based electrocatalysts for metal-air batteries and fuel cells.