多孔钙钛矿型氧还原催化剂在柔性铝空气电池中的应用研究

Porous Perovskite towards Oxygen Reduction Reaction in Flexible Aluminum-Air Battery

钙钛矿型催化材料作为贵金属的低成本替代物受到广泛关注,其用作氧还原反应催化剂具有非常可观活性和稳定性.目前相关工作主要集中在使用钙钛矿制备技术影响元素组成、形态、表面积和结构控制等方面.对于普遍存在的钙钛矿(ABO3)材料而言,制备过程煅烧温度较高导致合成材料比表面积通常较小,限制了其在非均相催化反应中活性的提升.本文借助无机模板SiO2制备具有高活性的大比表面的钙钛矿型催化材料La0.7Sr0.3MnO3(LSMO).测试结果表明,模板法LSMO具有非常可观的比表面积(31.1825 m^2·g^-1),用在柔性铝空气电池中放电电压相比于无模板法和溶胶凝胶法可分别提高8.2%和24.5%,且在大电流放电下性能衰退明显减缓.在电池变形状态下,输出电压可稳定在1.38 V以上.不仅为燃料电池商业化提供了解决方案,同时为未来可变性电源发展提供了新方向.

Perovskite-type catalytic materials have received wide attention as high-performance and low-cost alternatives to precious metal catalysts on the market at present,which have much considerable activity and stability as catalysts for oxygen reduction reactions.Current efforts are mainly focused on the use of perovskite make-up and preparation techniques to influence elemental composition,morphology,surface area,and structural control.For a typical perovskite oxide(ABO3),due to the high calcination temperature in the preparation process,the perovskite material usually has a small specific surface area,which limits the increase of activity in heterogeneous catalytic reactions.In this paper,the perovskite La0.7Sr0.3MnO3(LSMO)material with large specific surface and high catalytic activity is prepared by means of the SiO2 template.The physicochemical properties of the synthesized materials are characterized by scanning electron microscope(SEM),energy dispersed X-ray spectroscopy(EDS),X-ray diffraction(XRD)and BET.The catalytic activity of LSMO as an oxygen reduction reaction(ORR)catalyst is measured by a rotating disk test system.After that,the catalyst material is applied to a flexible aluminum-air battery and its discharge behavior and flexibility is studied and tested.The test results show that the LSMO prepared by template method has a large specific surface area(31.1825 m^2·g^-1),and pore volume(0.161113 cm^3·g^-1),and it also shows higher electrocatalytic activity in the electrochemical test system.When it is used in aluminum-air batteries,the activity of 3D porous LSMO is significantly better than that of sheet and bulk LSMO.The aluminum-air battery assembled by LSMO prepared by the template method has a higher discharge voltage(up to 1.46 V)at a constant current.Compared to the template-free method and the sol-gel method,the discharge voltage in flexible aluminum-air battery can be increased by 8.2% and 24.5%,respectively,and the performance degradation is significantly slowed during high-current discharge.The specific capacity and energy density of the battery are up to 1048.6 mA·h·g^-1 and 1020.6 mW·h·g^-1,respectively.When the battery is in a deformed state,its output voltage can be stabilized above 1.38 V.Once released,the voltage can be immediately restored to over 99% of the initial value.This paper not only provides a solution for the commercialization of fuel cell,but also provides a new direction for the future development of variable power supply.