Li Nan, Sun Mingzi, Xiao Jiaxiang, Ma Xiaoyu, Huang Lijuan, Li Hongyu, Xie Chao, Yang Yahui, Jiang Hao, Huang Bolong, Zhang Wenjun
College of Chemistry and Chemical Engineering, Hunan Normal University, Changsha, 410081, China.
Department of Applied Biology and Chemical Technology, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong SAR, 999077, China.
Small. 2024 Aug;20(31):e2401506. doi: 10.1002/smll.202401506. Epub 2024 Mar 3.
Reaching rapid reaction kinetics of oxygen reduction (ORR) and oxygen evolution reactions (OER) is critical for realizing efficient rechargeable zinc-air batteries (ZABs). Herein, a novel CoNi-CoN composite site containing CoNi alloyed nanoparticles and CoN moieties is first constructed in N-doped carbon nanosheet matrix (CoNi-CoN/C). Benefiting from the high electroactivity of CoNi-CoN composite sites and large surface area, CoNi-CoN/C shows a superior half-wave potential (0.88 V versus RHE) for ORR and a small overpotential (360 mV) for OER at 10 mA cm. Theoretical calculations have demonstrated that the introduction of CoNi alloys has modulated the electronic distributions near the CoN moiety, inducing the d-band center of CoNi-CoN composite site to shift down, thus stabilizing the valence state of Co active sites and balancing the adsorption of OER/ORR intermediates. Accordingly, the reaction energy trends exhibit optimized overpotentials for OER/ORR, leading to superior battery performances. For aqueous and flexible quasi-solid-state rechargeable ZABs with CoNi-CoN/C as catalyst, a large power density (250 mW cm) and high specific capacity (804 mAh g) are achieved. The in-depth understanding of the electroactivity enhancement mechanism of interactive metal nanoparticles and metal coordinated with nitrogen (MN) moieties is crucial for designing novel high-performance metal/nitrogen-doped carbon (M─N─C) catalysts.
实现氧还原反应（ORR）和析氧反应（OER）的快速反应动力学对于实现高效可充电锌空气电池（ZAB）至关重要。在此，首次在氮掺杂碳纳米片基质（CoNi-CoN/C）中构建了一种新型的包含CoNi合金纳米颗粒和CoN部分的CoNi-CoN复合位点。得益于CoNi-CoN复合位点的高电活性和大表面积，CoNi-CoN/C在ORR方面表现出优异的半波电位（相对于RHE为0.88 V），在10 mA cm时OER的过电位较小（360 mV）。理论计算表明，CoNi合金的引入调节了CoN部分附近的电子分布，导致CoNi-CoN复合位点的d带中心下移，从而稳定了Co活性位点的价态并平衡了OER/ORR中间体的吸附。因此，反应能量趋势显示出OER/ORR的过电位得到优化，从而带来优异的电池性能。对于以CoNi-CoN/C为催化剂的水系和柔性准固态可充电ZAB，实现了大功率密度（250 mW cm）和高比容量（804 mAh g）。深入了解相互作用金属纳米颗粒与氮配位金属（MN）部分的电活性增强机制对于设计新型高性能金属/氮掺杂碳（M─N─C）催化剂至关重要。
