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Download fileMussel-Inspired Polydopamine Coating for Enhanced Thermal Stability and Rate Performance of Graphite Anodes in Li-Ion Batteries
journal contribution
posted on 2016-05-16, 00:00 authored by Seong-Hyo Park, Hyeon
Jin Kim, Junmin Lee, You Kyeong Jeong, Jang Wook Choi, Hochun LeeDespite 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.