Bimetallic alloy nanoparticles embedded in N-doped carbon-based as an anode for potassium-ion storage material

Abstract

Metal-organic frameworks (MOFs) have great potential as anode materials for potassium-ion batteries (PIBs) due to their hierarchical porous structures, large number of reaction sites, and adjustable chemistry. However, the larger size of potassium ions adversely impacts the electrochemical performance and specific capacity. Therefore, it is imperative to develop novel electrode materials featuring distinctive structures for PIBs. This study achieved bimetal introduction by adding Ammonium ferric citrate during ZIF-67 growth. The resulting metal–organic skeleton of the bimetallic alloy nanoparticle (FeCo@PAZ-C) exhibits a core–shell structure and adorned with numerous microspheres on its surface, thereby offering an abundance of active sites for K+ storage. This architecture effectively reduces the diffusion path length for potassium ions and enhances electron transport pathways, ultimately contributing to improved performance. At 100 mA g−1 and after 500 cycles, the FeCo@PAZ-C electrode material demonstrated a stable specific capacity of 328 mAh/g with 95 % capacity retention. This self-sacrificing template method for MOFs offers a new approach to developing high-capacity and cycling-stable potassium-ion battery materials, broadening their potential applications.