A Charge Confinement Strategy for Boosting Interfacial Space Charge Storage in Manganese Ferrites Enabled by Highly Polarized Fluorinated‐Interfacial Layer for High‐Energy‐Density and Ultrafast Rechargeable Lithium‐Ion Batteries

Abstract

Transition metal conversion‐based anodes have recently re‐emerged as promising high‐performance energy storage materials by realizing their interfacial extra capacity. However, challenges persist in utilizing and maintaining its high activity particularly under rapidly repeated cycles, due to inherent capacity irreversibility, low conductivity, and unstable solid electrolyte interphase (SEI). Here, a novel charge confinement strategy employing a highly polarized, conductive interfacial layer of fluorinated carbon incorporated into galvanic replacement‐derived manganese ferrites is proposed to significantly boost interfacial space charge storage. A substantially high reversible capacity of 1376 mAh g−1 at 0.1 A g−1 is attained by developing the Li‐rich phase through spin‐polarized surface capacitance, coupled with highly polarized interfacial sites offered by the high electronegativity of fluorination. Furthermore, incorporating in situ formed LiF‐rich SEI from electrochemically active C─F bond can promote ionic/electronic transport, robustness, and volume change tolerance. Consequently, an exceptional rate performance of 513 mAh g−1 at 20 A g−1 is achieved with outstanding cyclability, delivering over 1100 mAh g−1 at 2 A g−1 after 300 cycles and further validating its practical application in stable full batteries. These insights demonstrate that rational surface modification to improve interfacial charge storage with stable modulated‐SEI can innovatively advance for high‐energy‐density conversion‐based anodes.