This mini review by Ming Gong and Hongjie Dai from Stanford University provides an overview of NiFe-based materials as highly active oxygen evolution reaction (OER) electrocatalysts. The review covers the early discovery and recent progress in the development of NiFe-based materials, including their chemical properties, synthetic methodologies, and catalytic performances. The advantages and disadvantages of different classes of NiFe-based compounds, such as NiFe alloys, electro-deposited films, and layered-double hydroxide nanoplates, are discussed. Mechanistic studies of the active phase of NiFe-based compounds are also introduced to provide insights into the nature of the active catalytic sites. The review highlights the potential of NiFe-based materials in applications such as water splitting and rechargeable metal-air batteries, including the development of an electrolyzer operating with a single AAA battery and high-performance rechargeable Zn-air batteries. The authors emphasize the need for further research to understand the detailed mechanisms of improved activity by Fe incorporation and to develop more advanced NiFe-based OER electrocatalysts with higher activity and stability.This mini review by Ming Gong and Hongjie Dai from Stanford University provides an overview of NiFe-based materials as highly active oxygen evolution reaction (OER) electrocatalysts. The review covers the early discovery and recent progress in the development of NiFe-based materials, including their chemical properties, synthetic methodologies, and catalytic performances. The advantages and disadvantages of different classes of NiFe-based compounds, such as NiFe alloys, electro-deposited films, and layered-double hydroxide nanoplates, are discussed. Mechanistic studies of the active phase of NiFe-based compounds are also introduced to provide insights into the nature of the active catalytic sites. The review highlights the potential of NiFe-based materials in applications such as water splitting and rechargeable metal-air batteries, including the development of an electrolyzer operating with a single AAA battery and high-performance rechargeable Zn-air batteries. The authors emphasize the need for further research to understand the detailed mechanisms of improved activity by Fe incorporation and to develop more advanced NiFe-based OER electrocatalysts with higher activity and stability.