Passivating Lithiated Graphite via Targeted Repair of SEI to Inhibit Exothermic Reactions in Early‐Stage of Thermal Runaway for Safer Lithium‐Ion Batteries

Abstract

The self‐exothermic in early stage of thermal runaway (TR) is blasting‐fuse for Li‐ion battery safety issues. The exothermic reaction between lithiated graphite (LiCx) and electrolyte accounts for onset of this behavior. However, preventing the deleterious reaction still encounters hurdles. Here, we manage to inhibit this reaction by passivating LiCx in real time via targeted repair of SEI. It is shown that 1,3,5‐trimethyl‐1,3,5‐tris(3,3,3‐trifluoropropyl)cyclotrisiloxane (D3F) can be triggered by LiCx to undergo ring‐opening polymerization at elevated temperature, so as to targeted repair of fractured SEI. Due to the high thermal stability of polymerized D3F, exothermic reaction between LiCx and electrolyte is inhibited. As a result, the self‐exothermic and TR trigger temperatures of pouch cell are increased from 159.6 and 194.2 °C to 300.5 and 329.7 °C. This work opens up a new avenue for designing functional additives to block initial exothermal reaction and inhibit TR in early stage.

A Review on the Recent Advances in Battery Development and Energy Storage Technologies

“…Because of its substantial specifc energy and elevated voltage, lithium-ion batteries (LIBs) have taken over as the primary power sources for portable gadgets and electric vehicles since their commercialization in the late 1990s [73]. Nonetheless, in recent years, due to the widespread promotion and use of LIBs, numerous safety incidents caused by thermal runaway (TR) have occurred worldwide, raising serious concerns about LIBs, particularly in grid-scale energy storage [73]. Te reaction can be separated into early, medium, and late stages depending on the time-sequence of TR.…”