Wang Yuyang, Gao Yaping, Ma Lixia, Xue Yanzhong, Liu Zong-Huai, Cui Huali, Zhang Nan, Jiang Ruibin
Key Laboratory of Applied Surface and Colloid Chemistry, National Ministry of Education, Shaanxi Key Laboratory for Advanced Energy Devices, Shaanxi Engineering Lab for Advanced Energy Technology, School of Materials Science and Engineering, Shaanxi Normal University, Xi'an 710119, China.
School of Chemistry and Chemical Engineering, Yanan University, Yan'an 716000, China.
ACS Appl Mater Interfaces. 2023 Apr 5;15(13):16732-16743. doi: 10.1021/acsami.2c23232. Epub 2023 Mar 27.
The sluggish four-electron processes of the oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) limit the development of rechargeable Zn-air batteries (RZABs). Highly efficient ORR/OER bifunctional electrocatalysts are therefore highly desired for the commercialization of RZABs in large scale. Herein, the Fe-N-C (ORR active sites) and NiFe-LDH clusters (OER active sites) are successfully integrated within a NiFe-LDH/Fe,N-CB electrocatalyst. The NiFe-LDH/Fe,N-CB electrocatalyst is first prepared by the introduction of Fe-N into carbon black (CB), followed by the growth of NiFe-LDH clusters. The cluster nature of NiFe-LDH effectively avoids the blocking of Fe-N-C ORR active centers and affords excellent OER activity. The NiFe-LDH/Fe,N-CB electrocatalyst thus exhibits an excellent bifunctional ORR and OER performance, with a potential gap of only 0.71 V. The NiFe-LDH/Fe,N-CB-based RZAB exhibits an open-circuit voltage of 1.565 V and a specific capacity of 731 mAh g, which is much better than the RZAB composed of Pt/C and IrO. Particularly, the NiFe-LDH/Fe,N-CB-based RZAB displays excellent long-term charging/discharging cyclic stability and rechargeability. Even at a large charging/discharging current density (20 mA cm), the charging/discharging voltage gap is only ∼1.33 V and exhibits an increase smaller than 5% after 140 cycles. This work provides a new low-cost bifunctional ORR/OER electrocatalyst with high activity and superior long-term stability and will be helpful to the commercialization of RZAB in large scale.
氧还原反应（ORR）和析氧反应（OER）缓慢的四电子过程限制了可充电锌空气电池（RZAB）的发展。因此，高效的ORR/OER双功能电催化剂对于RZAB的大规模商业化至关重要。在此，Fe-N-C（ORR活性位点）和NiFe-LDH簇（OER活性位点）成功整合到NiFe-LDH/Fe,N-CB电催化剂中。NiFe-LDH/Fe,N-CB电催化剂首先通过将Fe-N引入炭黑（CB）中制备，然后生长NiFe-LDH簇。NiFe-LDH的簇状性质有效避免了Fe-N-C ORR活性中心的阻塞，并提供了优异的OER活性。因此，NiFe-LDH/Fe,N-CB电催化剂表现出优异的双功能ORR和OER性能，电位差仅为0.71 V。基于NiFe-LDH/Fe,N-CB的RZAB表现出1.565 V的开路电压和731 mAh g的比容量，这比由Pt/C和IrO组成的RZAB要好得多。特别是，基于NiFe-LDH/Fe,N-CB的RZAB表现出优异的长期充放电循环稳定性和可充电性。即使在大的充放电电流密度（20 mA cm）下，充放电电压差仅为~1.33 V，并且在140次循环后增加小于5%。这项工作提供了一种新型的低成本双功能ORR/OER电催化剂，具有高活性和优异的长期稳定性，将有助于RZAB的大规模商业化。
