摘要
Lattice contraction increases defect oxygen species and modifies surface transition-metal redox states. • HEP-Nd-0.3 achieves a bifunctional potential gap ΔE = 0.77 V with OER overpotential of 290 mV and ORR half-wave potential of 0.75 V. • Zn-air battery delivers 115 mW cm⁻² peak power density and stable operation for over 340 h. • A-site lattice modulation alone enhances intrinsic OER/ORR activity without aliovalent doping. Rechargeable zinc–air batteries require bifunctional air-cathode catalysts capable of efficiently catalyzing both the oxygen reduction reaction (ORR) and oxygen evolution reaction (OER). Herein, La 1-x Nd x (Cr 0.2 Mn 0.2 Fe 0.2 Co 0.2 Ni 0.2 ) O 3 (x = 0, 0.1, 0.2, and 0.3) high-entropy perovskites (HEP) were synthesized to examine the influence of isovalent Nd³⁺ substitution at the A site on bifunctional oxygen electrocatalysis. Replacement of La³⁺ with smaller Nd³⁺ preserves the nominal A-site charge while inducing lattice contraction and modifying the surface chemical environment of the multication perovskite. Among the investigated compositions, HEP-Nd-0.3 exhibits the best bifunctional activity, delivering an OER overpotential of 290 mV at 10 mA cm −2 , an ORR half-wave potential of 0.75 V versus RHE, and a bifunctional potential gap of 0.77 V. When used as the air-cathode catalyst in a rechargeable zinc–air battery, HEP-Nd-0.3 achieves a peak power density of 115 mW cm −2 and stable charge–discharge operation for >340 h. The enhanced performance is associated with Nd-content-dependent variations in lattice structure, surface oxygen chemistry, electrochemically accessible surface area, and charge-transfer characteristics. These results identify isovalent rare-earth A-site substitution as a practical strategy for tuning high-entropy perovskite oxygen electrocatalysts. Download: Download high-res image (313KB) Download: Download full-size image
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