High Structural Stability and Reaction Mechanism of Porous Carbon Nanobox Encapsulated Monodisperse CoP Nanoparticles for High‐Performance Lithium‐Ion Battery

Abstract Transition metal phosphides (TMPs) are perplexed by the low electronic/ionic conductivity, volume variations, and unstable reaction interfaces. To tackle these issues, herein, we have proposed a low‐temperature phosphorization strategy by reactions between Co‐based metal‐organic frameworks (MOF) and sodium dihydric hypophosphite to encapsulate monodisperse CoP nanoparticle (∼12 nm) into MOF‐derived hollow and porous carbon nanobox (CoP@PCB). Compared to bare CoP, such CoP@PCB electrode has shown remarkable electrochemical performance, which is highly ascribed to its robust structural feature, pre‐reserved voids, monodisperse CoP nanoparticles, and stable reaction interfaces, as well as fast reaction kinetics. Moreover, the good electrochemical properties of CoP@PCB//LiFePO₄ full cells have demonstrated practical possibility. The formation of Co and Li₃P as discharged products has corroborated the redox conversion reaction mechanism, as assessed by in‐situ X‐ray diffractions. The favorable function of the carbon shell in boosting both electronic conductivity and lowering diffusion energy barriers has been confirmed by theoretical calculations, demonstrating an important synergistic effect.