Heteroatom-Induced Electronic Structure Modulation of Vertically Oriented Oxygen Vacancy-Rich NiFe Layered Double Oxide Nanoflakes To Boost Bifunctional Catalytic Activity in Li-O2 Battery.

NiFe-based transition metal oxide (NiFe-TMO) has been identified as an effective electrocatalyst for lithium-oxygen (Li-O2) batteries due to its superior catalytic activity for oxygen evolution reaction. Improving the bifunctional catalytic ability of NiFe-TMO is essential for the further performance improvement of Li-O2 batteries. Herein, we regulated the electronic structure of free-standing NiFe LDO nanosheets array via introducing foreign Co ion to improve its bifunctional catalytic activity in Li-O2 batteries. Combined with well-designed electrode architecture and the deliberately modified surface electronic structure, this strategy markedly alleviates polarization problem in terms of low overpotential (0.98 V), and the discharge voltage within 110 cycles remains stable at 2.89 V without significant attenuation. This study illustrates an intimate connection between electronic structure engineering and catalytic activity optimization that is critical for the rational design of Li-O2 batteries.