Single‐Atom Pd‐N<sub>4</sub> Catalysis for Stable Low‐Overpotential Lithium‐Oxygen Battery
Jian Zheng, Wenjing Zhang, Ruoyu Wang, Junkai Wang, Yanwu Zhai, Xiangfeng Liu
Abstract
Abstract The critical challenge for Li‐O 2 batteries lies in the large charge overpotential, leading to undesirable side reactions and inferior cycle stability. Single‐atom catalysts have shown promising prospects in expediting the kinetics of oxygen evolution reaction (OER) for Li‐O 2 batteries. However, a present practical drawback is the limited understanding of the correlation between the unique atomic structures and the OER mechanism. Herein, a template‐assisted strategy is reported to synthesize atomically dispersed Pd anchored on N‐doped carbon spheres as cathode catalysts. Benefiting from the well‐defined Pd‐N 4 moiety, the morphology and distribution of Li 2 O 2 products are distinctly regulated with optimized decomposition reversibility. Theoretical simulations reveal that the unique configuration of Pd‐N 4 will contribute to the electron transfer from Pd atoms to the adjacent N atoms, which turns the originally electroneutral Pd into positively charged and downshifts the d‐band center and therefore weakens its adsorption energy with the intermediates. The Li‐O 2 batteries with Pd SAs/NC cathode achieve a charge overpotential of only 0.24 V and sustainable low‐overpotential cycling stability (500 mA g −1 ), and can retain a low charge voltage to a very high capacity of 10 000 mAh g −1 . This work provides some insights into designing efficient single‐atom catalysts for stable low‐overpotential Li‐O 2 batteries.