posted on 2021-11-05, 20:43authored byYoun-Ki Lee, Cheol-Ho Lee, Gil-Seong Kang, KwangSup Eom, Se Youn Cho, Sungho Lee, Han-Ik Joh
Fluorine
(F) atoms with the highest electronegativity and low polarizability
can easily modify the surface and composition of carbon-based electrode
materials. However, this is accompanied by complete irreversibility
and uncontrolled reactivity, thus hindering their use in rechargeable
electronic devices. Therefore, understanding the electrochemical effects
of the C–F configuration might lead to achieving superior electrochemical
properties. Here, we demonstrate that the fluorinated and simultaneously
reduced graphene oxide (FrGO) was easily synthesized through direct
gas fluorination. The as-prepared 11%-FrGO electrode exhibited a high
capacity (1365 mAh g–1 at 0.1 A g–1), remarkable rate capability, and good stability (64% retention
after 1000 cycles at 5 A g–1). Furthermore, the
annealed FrGO (11%-FrGO(A)) electrode in which the C–F bond
configurations were controlled by facile thermal treatment shows long-term
stability (80% retention after 1000 cycles at 5 A g–1). Above a certain content, F atoms enhance Li-ion adsorption and
electron transfer, accelerate Li-ion diffusion, and facilitate the
formation of a solid electrolyte interphase layer. In particular,
the C–F configuration plays a significant role in retaining
the capacity under harsh recharging conditions. The results in this
study could provide valuable insights into the field of rechargeable
devices.