Role of Catalytic Conversions of Ethylene Carbonate, Water, and HF in Forming the Solid-Electrolyte Interphase of Li-Ion Batteries

Compared to aqueous electrolytes, fundamental understanding of the chemical and electrochemical processes occurring in non-aqueous electrolytes is far less developed. This no different for Li-ion battery (LiB) where many questions regarding solid-electrolyte interphase (SEI) on anode side remain unanswered, including its composition, mechanism formation, impact LiB performance. Here, we present a detailed experimental theoretical study electrochemistry ethylene carbonate (EC) relationship with trace amounts water HF across vast range electrode materials, from well-ordered single crystals realistic graphite electrodes. We reveal electrocatalytic nature EC, HF, electroreductions at all interfaces, unveil catalytic role EC electroreduction. Moreover, show that these reactions are connected closed cycle by take place either electrode/electrolyte interface or bulk electrolyte demonstrate composition SEI depends predominantly balance between (electro)chemistry water, HF.