Developing fast‐charging Zn–air batteries is crucial for widening their application but remains challenging owing to the limitation of sluggish oxygen evolution reaction (OER) kinetics and insufficient active sites of electrocatalysts. To solve this issue, a reconstructed amorphous FeCoNiSx electrocatalyst with high density of efficient active sites, yielding low OER overpotentials of 202, 255, and 323 mV at 10, 100, and 500 mA cm−2, respectively, is developed for fast‐charging Zn–air batteries with low charging voltages at 100–400 mA cm−2. Furthermore, the fabricated 3241.8 mAh (20 mA cm−2, 25 °C) quasi‐solid Zn–air battery shows long lifetime of 500 h at −10 and 25 °C as well as 150 h at 40 °C under charging 100 mA cm−2. The detailed characterizations combine with density functional theory calculations indicate that the defect‐rich crystalline/amorphous ternary metal (oxy)hydroxide forms by the reconstruction of amorphous multi‐metallic sulfide, where the electron coupling effect among multi‐active sites and migration of intermediate O* from Ni site to the Fe site breaks the scaling relationship to lead to a low theoretical OER overpotential of 170 mV, accounting for the outstanding fast‐charging property. This work not only provides insights into designing advanced OER catalysts by the self‐reconstruction of the pre‐catalyst but also pioneers a pathway for practical fast‐charging Zn–air batteries.
It remains challenging for pure‐phase catalysts to achieve high performance during the electrochemical oxygen reduction reaction to overcome the sluggish kinetics without the assistance of extrinsic conditions. Herein, a series of pristine perovskites, i.e., AMnO3 (A = Ca, Sr, and Ba), are proposed with various octahedron stacking configurations to demonstrate the cooperative catalysis over SrMnO3 jointly explored by experiments and first‐principles calculations. Comparing with the unitary stacking of coordination units in CaMnO3 or BaMnO3, the intrinsic SrMnO3 with a mixture of corner‐sharing and face‐sharing octahedron stacking configurations demonstrates superior activity (Ehalf‐wave = 0.81 V), and charge–discharge stability over 400 h without the voltage gap (≈0.8 V) increasing in zinc–air batteries. The theoretical study reveals that, on the SrMnO3(110) surface, the active sites switch from coordinatively unsaturated atop Mn (*OO, *OOH) to Mn–Mn bridge (*O, *OH). Therefore, the intrinsic dual coordination environments of Mn–Ocorner and Mn–Oface enable cooperative modulation of the interaction strength of the oxygen intermediates with the surface, inducing the decrease of the *OH desorption energy (rate‐limiting step) unrestricted by scaling relationships with the overpotential of ≈0.28 V. This finding provides insights into catalyst design through screening intrinsic structures with multiple coordination unit stacking configurations.
The
cooperation among different surface coordination environments
is beneficial to reach a moderate interaction with the oxygen intermediates
and therefore achieve an optimal electrochemical oxygen reduction
reaction (ORR) activity. A facilely effective strategy is essential
to regulate the electronic structure and then the ratio of Mn3+ to Mn4+ in the intrinsically strong Mn–O
bonding SmMn2O5. In this work, a two-step photochemical
reduction method was adopted to load the Pd nanoparticles on the SmMn2O5 nanorods to form an atomic interface contact.
The optimized catalyst 7.5 wt % Pd@SmMn2O5 shows
an excellent activity with the half-wave potential 0.83 V (vs RHE)
and the charge-transfer resistance ∼38 Ω smaller than
that of commercial platinum. The electrons transferring from Pd to
p-type SmMn2O5 at the interface contribute to
the moderate d-band center and Mn valence and then the neither too
strong nor too weak interaction with oxygen intermediates. The accumulated
electrons on the conduction band of mullite occupy the anti-bonding
states of oxygen in mullite and then activate more oxygen, which favors
the labile oxygen participant adsorbate evolving mechanism (LAM) for
the ORR process. The assembled Zn–air battery exhibits a high
peak power density of ∼236 mW/cm2 and a large open-circuit
potential of ∼1.43 V. This work provides insights into the
activity optimization of the intrinsically stable catalysts from the
aspect of the metal–semiconductor interface.
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