Interstitial Cobalt Nitrides (CoxN): Holistic Frontiers in Energy Storage and Catalysis

Abstract

Cobalt nitrides (Co_xN), with their unique interstitial architecture, have emerged as a class of earth-abundant and cost-effective materials with exceptional multifunctionality in electrochemical energy storage and catalysis. Their distinctive physicochemical properties, such as flexible oxidation states, tunable electrical conductivity, and metallic-like characteristics, make them highly attractive for a wide range of applications, including lithium-ion batteries (LiBs), supercapacitors (SCs), rechargeable zinc-air batteries (RZABs), and electrocatalytic reactions (HER, OER, ORR). The growing interest in Co_xN-based materials is evident from the surge in research publications in recent years. However, despite their transformative potential, there is a lack of comprehensive reviews that holistically address their multifunctional roles across energy storage and conversion technologies. This review aims to fill this gap by providing an up-to-date overview of rational fabrication strategies for Co_xN-based materials, with a focus on tailoring their compositions and morphologies to optimize performance as electrodes and electrocatalysts. Furthermore, this work offers insights into the structure-property-performance relationships of Co_xN materials and provides guidance for future research directions to develop more efficient, durable, and sustainable energy technologies.