Redox-active ferrocene upgrading PEO electrolyte for durable all-solid-state lithium-metal batteries
Qingyue Han, Suqing Wang, Wenhao Ren, Fangdan Zhang, Zhanbo Tang, Wang Ju, Haihui Wang
Abstract
Poly (ethylene oxide) (PEO)-based electrolytes are under intense research because of their high safety, low cost and easy to scale fabrication. But several barriers, such as the poor ionic conductivity , slow reaction kinetics and uneven lithium deposition, still prevent their practical implementation. Herein, ferrocene (Fc) is utilized as a novel redox mediator filler for PEO based-electrolyte to optimize the performance of all-solid-state Li-metal battery . In addition to enhancing the ionic conductivity of electrolyte via Fe–O coordination interaction and Li-cyclopentadienyl ligands cation-π interaction, Fc can also regulate uniform lithium ionic flux over Li metal and inhibit lithium dendrite growth. Moreover, Fc can accelerate the electron transfer and reaction kinetic of LiFePO 4 cathode because of its properties of electron-transfer mediator. As a result, the all-solid-state LiFePO 4 /PEO electrolyte/Li battery with the addition of Fc shows notable cycling stability. It delivers an initial capacity of 158.2 mAh g −1 at 0.5 C and maintains 146.1 mAh g −1 after 300 cycles with a high capacity retention of 92.5%. This work offers a convenient method for durable all-solid-state lithium-metal batteries.