title: Mussel-Inspired Polydopamine Coating for Enhanced Thermal Stability and Rate Performance of Graphite Anodes in Li-Ion Batteries.
abstract: Despite two decades of commercial history, it remains very difficult to simultaneously achieve both high rate capability and thermal stability in the graphite anodes of Li-ion batteries because the stable solid electrolyte interphase (SEI) layer, which is essential for thermal stability, impedes facile Li(+) ion transport at the interface. Here, we resolve this longstanding challenge using a mussel-inspired polydopamine (PD) coating via a simple immersion process. The nanometer-thick PD coating layer allows the formation of an SEI layer on the coating surface without perturbing the intrinsic properties of the SEI layer of the graphite anodes. PD-coated graphite exhibits far better performances in cycling test at 60 °C and storage test at 90 °C than bare graphite. The PD-coated graphite also displays superior rate capability during both lithiation and delithiation. As evidenced by surface free energy analysis, the enhanced performance of the PD-coated graphite can be ascribed to the Lewis basicity of the PD, which scavenges harmful hydrofluoric acid and forms an intermediate triple-body complex among a Li(+) ion, solvent molecules, and the PD's basic site. The usefulness of the proposed PD coating can be expanded to various electrodes in rechargeable batteries that suffer from poor thermal stability and interfacial kinetics.
authors.affiliation: Department of Energy Systems Engineering, Daegu Gyeongbuk Institute of Science and Technology , Daegu 42988, South Korea.
authors.forename: Seong-Hyo
authors.initials: SH
authors.lastname: Park
authors.affiliation: Department of Energy Systems Engineering, Daegu Gyeongbuk Institute of Science and Technology , Daegu 42988, South Korea.
authors.forename: Hyeon Jin
authors.initials: HJ
authors.lastname: Kim
authors.affiliation: Department of Energy Systems Engineering, Daegu Gyeongbuk Institute of Science and Technology , Daegu 42988, South Korea.
authors.forename: Junmin
authors.initials: J
authors.lastname: Lee
authors.affiliation: Graduate School of Energy, Environment, Water, and Sustainability and KAIST Institute NanoCentury, Korea Advanced Institute of Science and Technology , Daejeon 34141, South Korea.
authors.forename: You Kyeong
authors.initials: YK
authors.lastname: Jeong
authors.affiliation: Graduate School of Energy, Environment, Water, and Sustainability and KAIST Institute NanoCentury, Korea Advanced Institute of Science and Technology , Daejeon 34141, South Korea.
authors.forename: Jang Wook
authors.initials: JW
authors.lastname: Choi
authors.affiliation: Department of Energy Systems Engineering, Daegu Gyeongbuk Institute of Science and Technology , Daegu 42988, South Korea.
authors.forename: Hochun
authors.initials: H
authors.lastname: Lee
keywords: Dopamine; Graphite; Solid electrolyte interphase layer; Surface free energy; lithium-ion batteries