The fluorination-assisted dealloying synthesis of porous reduced graphene oxide-FeF2@carbon for high-performance lithium-ion battery and the exploration of its electrochemical mechanism

Abstract

With its high theoretical capacity and low cost, FeF₂ possesses a great potential for applications in next-generation lithium-ion batteries. However, its poor conductivity and dramatic volume change during the charge/discharge process limit its practical application. To maximize available electrochemical performance, a novel porous reduced graphene oxide-FeF₂@carbon (rGO-FeF₂@C) composite that exhibits a high reversible capacity of 430 mA h g⁻¹ and maintains 400 mA h g⁻¹ even after 50 cycles at 0.08 A g⁻¹ has been successfully synthesized by a dealloying method, which also demonstrated superior rate performance from 0.08 A g⁻¹ to 1.00 A g⁻¹. The result shows that such a structure and method are an effective strategy to achieve good performance for the FeF₂ cathode. A novel phenomenon that a lower charge voltage will induce a higher discharge plateau is observed and the possible assumption is raised.