Suppressing Side Reaction via Fluorinated Core–Shell Electrolyte for Durable 4.8 V Li‐Rich Batteries

ABSTRACT Lithium‐rich Mn‐based cathode materials with high energy density hold promise for enabling > 500 Wh kg −1 batteries; however, the reactive oxygen species (ROS) generated at high voltages trigger electrolyte decomposition and gas evolution, posing severe interfacial stability challenges and safety risks. Herein, a “side‐reaction inhibition” strategy is proposed by employing a bulky, ROS‐stable diluent to modulate core–shell solvation structures and shield highly reactive solvents, effectively suppressing interfacial side reactions. As a result, a 2.5 Ah pouch cell with an ultrahigh areal capacity of 9.6 mAh cm −2 achieves 502.7 Wh kg −1 and delivers a capacity retention of 89.85% after 50 cycles at 0.1 C, while significantly suppressing gas evolution. This work provides novel insights into electrolyte design for high‐voltage lithium metal batteries through targeted mitigation of reactive oxygen species side effects.