LAUSR

An atomically dispersed FeCo-NC material with the 3D flower-like morphology was used as a unique substrate for the controllable deposition of ultrasmall NiFe layered double hydroxide nanodots (termed as NiFe-NDs) to simultaneously promote the sluggish kinetics of oxygen reduction reaction (ORR) and oxygen evolution reaction (OER). The size-limiting growth of NiFe-NDs (~4.0 nm in diameter) was realized via the confinement of the 3D flower-like mesoporous structure and the rich N/O functionality of FeCo-NC. Benefiting from the distinctive structure with the simultaneously maximum exposure of both OER and ORR active sites, the NiFe-ND/FeCo-NC composite showed an ORR halfwave potential of 0.85 V and an OER potential of 1.66 V in 0.1 mol L −1 KOH at 10.0 mA cm −2 . In-situ Raman analysis suggested the activity of OER was derived from the Ni sites on NiFe-ND/FeCo-NC. Moreover, the NiFe-ND/FeCo-NC-assembled Zn-air battery (ZAB) exhibited a very small discharge- charge voltage gap of 0.87 V at 20 mA cm −2 and robust cycling stability. Furthermore, the NiFe-ND/FeCo-NC composite was also applicable for fabricating all-solid-state ZAB to power wearable electronics with superior cycling stability under deformation. Our work could enlighten a new applicable branch of atomically dispersed metal-nitrogen-carbon materials as unique substrates for fabricating multifunctional electrocatalysts. 单原子分散的FeCo-NC材料, 具有特殊的花状结构和原子级 分散Fe/Co位点, 适用于可控沉积超小NiFe水滑石纳米点(NiFe- ND), 从而制备具有优异氧还原(ORR)和氧析出(OER)性能的双功 能催化材料. FeCo-NC材料本身具有三维立体花状介孔结构和丰 富的N/O功能位点, 可以实现对NiFe-ND尺寸的有效控制(直径约 4 nm), 使得制备的特殊复合材料的OER和ORR活性位暴露度达最 大值. 电化学测试表明在0.1 mol L −1 KOH电解液中NiFe-ND/FeCo-NC的ORR半波电势为0.85 V, 当电流密度为10 mA cm −2 时的 OER电势为1.66 V. 原位拉曼结果进一步证实了NiFe-ND/FeCo-NC 材料优良的OER活性来源于电化学过程中产生的丰富Ni(Fe)OOH 活性相. 采用NiFe-ND/FeCo-NC组装的锌空气电池具有较小的充 放电电压差(0.87 V, 20 mA cm −2 )和持久的循环稳定性. 同时, NiFe-ND/FeCo-NC也可以应用于全固态锌空气电池, 即使在形变 的情况下仍然具有良好的循环稳定性. 本工作可为单原子金属氮 碳催化剂作为特殊基底材料应用于新型多功能催化剂的研发提供 指导.