Ethylene Carbonate Free Electrolyte for Wide‐Temperature 4.5 V Lithium‐Ion Battery

ABSTRACT Ethylene carbonate (EC) is a key solvent to establish the stable solid electrolyte interphase (SEI) on the graphite anode in lithium‐ion batteries. However, it decomposes at >4.3 V vs. Li/Li+ and its high melting point (36.4 °C) significantly restricts its applicability in a wide‐temperature (from −20 to 60 °C) scenario. Although substituting EC with high‐voltage‐tolerant solvents partially alleviates these limitations, the lack of robust SEI formation inevitably induces graphite exfoliation and electrolyte decomposition. To overcome this challenge, we propose a low‐coordination‐number solvent, i.e., ethyl methyl carbonate (EMC), which can help construct an anion‐dominated solvation sheath, followed by optimizing the solvation structure through the incorporation of a voltage‐resistant, wide‐temperature solvent with properties analogous to EC. This approach synergistically integrates interfacial chemistry and solvation thermodynamics, thereby achieving both SEI stability and high ion transport kinetics. The developed electrolyte demonstrates exceptional thermal stability, enhanced interfacial compatibility, and superior high‐voltage tolerance, enabling stable Graphite (Gr) ||LiNi 0.8 Co 0.1 Mn 0.1 O 2 (NCM811) full cells cycled at 4.5 V.