Thermal Runaway of Nonflammable Localized High-Concentration Electrolytes for Practical LiNi_0.8Mn_0.1Co_0.1O₂|Graphite-SiO Pouch Cells

With continuous improvement of batteries in energy density, enhancing their safety is becoming increasingly urgent. Herein, practical high energy density LiNi_0.8Mn_0.1Co_0.1O₂|graphite-SiO pouch cell with nonflammable localized high concentration electrolyte (LHCE) is proposed that presents unique self-discharge characteristic before thermal runaway (TR), thus effectively reducing safety hazards. Compared with the reference electrolyte, pouch cell with nonflammable LHCE can increase self-generated heat temperature by 4.4 °C, increase TR triggering temperature by 47.3 °C, decrease the TR highest temperature by 71.8 °C, and extend the time from self-generated heat to triggering TR by ≈8 h. In addition, the cell with nonflammable LHCE presents superior high voltage cycle stability, attributed to the formation of robust inorganic-rich electrode–electrolyte interphase. The strategy represents a pivotal step forward for practical high energy and high safety batteries.