Low‐Reactivity Electrolytes Achieve Safe and Durable Energy‐Dense NCM955|SiC Pouch Cells

Abstract

Solvent coordination in conventional electrolytes demonstrates poor thermal compatibility with energy‐dense lithium‐ion batteries, resulting in significant reactivity and the potential for thermal failure. Herein, a low‐reactivity electrolyte (LRE) engineered through anionic coordination is developed to regulate thermally‐driven interfacial and crosstalk reactions, achieving inherent safety in 300 Wh kg−1 LiNi0.9Mn0.05Co 0.05O2|Graphite@10%SiO (NCM955|SiC) pouch cells. The anionic coordination complexes demonstrate exceptional thermal stability when interfacing with the lithiated anode, effectively suppressing both exothermic reactions and flammable gas evolution. In situ temperature‐dependent X ‐ ray diffraction confirms that LRE stabilizes the lithiated anode phase up to 184 °C, a 51 °C improvement over conventional electrolytes, thereby retarding exothermic electrolyte reduction. Notably, a subsequent 27.3% decrease in reductive gases mitigates crosstalk‐induced cathode degradation while reducing combustion risks in pouch cells when employing LRE. Practical evaluation in 2.4 Ah NCM955|SiC pouch cells reveals that LRE sustains exceptional stability up to 255.0 °C under heating, significantly outperforming conventional cells that failed at 165.6 °C with violent combustion. Furthermore, the 2.4Ah pouch cell maintains an impressive 84.5% capacity retention after 800 cycles, indicating enhanced electrochemical stability and longevity. This work highlights the potential of coordination chemistry in developing safe and durable energy‐dense batteries.