Contents lists available at ScienceDirect Journal of Power Sources journal homepage: www.elsevier.com/locate/jpowsour In operando measurements of kinetics of solid electrolyte interphase formation in lithium-ion batteries Tibebu Alemu a , Sylvia Ayu Pradanawati a,b , Shih-Chang Chang a , Pin-Ling Lin a , Yu-Lin Kuo c , Quoc-Thai Pham a , Chia-Hung Su d , Fu-Ming Wang a,e,* a Graduate Institute of Applied Science and Technology, National Taiwan University of Science and Technology, Taipei, Taiwan b Department of Physics Energy Engineering, Surya University, Banten, Indonesia c Department of Mechanical Engineering, National Taiwan University of Science and Technology, Taipei, Taiwan d Graduate School of Biochemical Engineering, Ming Chi University of Technology, New-Taipei City, Taiwan e Sustainable Energy Center, National Taiwan University of Science and Technology, Taipei, Taiwan HIGHLIGHTS • In operando SPR and EQCM reveal the in-time kinetic reaction of electrolyte. • In operando SPR and EQCM predicts SEI formation for graphite and Si an- odes. • LiMB is a good salt additive for Si anode to inhibit the SEI formation. • LiTFB is a good salt additive for gra- phite anode to reinforce the SEI for- mation. GRAPHICAL ABSTRACT ARTICLE INFO Keywords: Surface plasma resonance Quartz crystal microbalance Solid electrolyte interphase In-operando Lithium ion battery ABSTRACT This study applied two in operando techniques to reveal the reaction kinetics of solid electrolyte interphase formation on electrolyte and benzimidazole salt additives. The results obtained from studying interface effects reveal changes in solid electrolyte interphase mass, reflection angle, and reflection intensity within the elec- trolyte additives in accordance with electron-withdrawing and electron-donating substitutions. Surface plasma resonance results reveal that the electrolyte containing the electron-withdrawing salt additive exhibited the highest rate constant (774 s -1 ) of the binding reaction between the benzimidazole additive and Au surface, indicating the strong reaction effects on Au. The electrolyte containing the electron-withdrawing salt additive accelerates and facilitates the dissociation reaction of the ethylene carbonate–lithium ion (EC–Li + ) ionic cluster. From the quartz crystal microbalance results, the electrolyte containing the electron-withdrawing salt additive shows the greatest solid electrolyte interphase mass (14.84 μg cm -2 ), representing the intense dissociation re- actions of the EC–Li + ionic cluster as well as solid electrolyte interphase formation and recombination. In this study, selecting a high rate constant and high binding strength of the EC–Li + ionic cluster on the electrode surface enhance solid electrolyte interphase formation and battery performance. https://doi.org/10.1016/j.jpowsour.2018.08.039 Received 3 May 2018; Received in revised form 21 July 2018; Accepted 12 August 2018 * Corresponding author. IB 606, 43 Keelung Road, Section 4, Taipei, 106, Taiwan. E-mail address: mccabe@mail.ntust.edu.tw (F.-M. Wang). Journal of Power Sources 400 (2018) 426–433 0378-7753/ © 2018 Elsevier B.V. All rights reserved. T