title: Using atomic layer deposition to hinder solvent decomposition in lithium ion batteries: first-principles modeling and experimental studies.
abstract: Passivating lithium ion (Li) battery electrode surfaces to prevent electrolyte decomposition is critical for battery operations. Recent work on conformal atomic layer deposition (ALD) coating of anodes and cathodes has shown significant technological promise. ALD further provides well-characterized model platforms for understanding electrolyte decomposition initiated by electron tunneling through a passivating layer. First-principles calculations reveal two regimes of electron transfer to adsorbed ethylene carbonate molecules (EC, a main component of commercial electrolyte), depending on whether the electrode is alumina coated. On bare Li metal electrode surfaces, EC accepts electrons and decomposes within picoseconds. In contrast, constrained density functional theory calculations in an ultrahigh vacuum setting show that, with the oxide coating, e(-) tunneling to the adsorbed EC falls within the nonadiabatic regime. Here the molecular reorganization energy, computed in the harmonic approximation, plays a key role in slowing down electron transfer. Ab initio molecular dynamics simulations conducted at liquid EC electrode interfaces are consistent with the view that reactions and electron transfer occur right at the interface. Microgravimetric measurements demonstrate that the ALD coating decreases electrolyte decomposition and corroborates the theoretical predictions.
authors.affiliation: Sandia National Laboratories, MS 1415 and 0888, Albuquerque, New Mexico 87185, USA. kleung@sandia.gov
authors.forename: Kevin
authors.initials: K
authors.lastname: Leung
authors.forename: Yue
authors.initials: Y
authors.lastname: Qi
authors.forename: Kevin R
authors.initials: KR
authors.lastname: Zavadil
authors.forename: Yoon Seok
authors.initials: YS
authors.lastname: Jung
authors.forename: Anne C
authors.initials: AC
authors.lastname: Dillon
authors.forename: Andrew S
authors.initials: AS
authors.lastname: Cavanagh
authors.forename: Se-Hee
authors.initials: SH
authors.lastname: Lee
authors.forename: Steven M
authors.initials: SM
authors.lastname: George