Amorphous FeP@porous carbon nanofibers with sterically conductive networks for stable potassium-ion storage.

Structural instability in electrode materials is a critical barrier to the practical application of potassium-ion batteries (PIBs) in terms of long-term durability. To overcome this, we integrated amorphous FeP within continuous three-dimensional (3D) carbon fiber networks, fabricated through an electrospinning process. The amorphous structure of FeP facilitates isotropic volume expansion, effectively distributing stress uniformly across the electrode and mitigating degradation during cycling. Additionally, the loosely packed atomic arrangement and interconnected 3D conductive framework enable smoother potassium-ion diffusion, thereby enhancing the kinetic performance. Therefore, the well-designed amorphous FeP/porous carbon nanofibers (A-FeP@PCNFs) exhibit a remarkable specific capacity of 358.3 mA h g-1 at 0.1 A g-1 and demonstrate exceptional cycling durability, retaining a reversible capacity of 152.0 mA h g-1 after 2400 cycles at 3 A g-1. This innovative design offers a robust approach for developing excellent electrochemical performance anode materials with superior structural stability and rapid electrochemical response, advancing the potential of PIBs in energy storage applications.