Delocalized electrolyte design enables 600 Wh kg^-1 lithium metal pouch cells

The development of high-energy lithium metal batteries (LMBs) is essential for advances in next-generation energy storage and electric vehicle technologies^1-3. Nevertheless, the practical applications of LMBs are constrained by current electrolyte designs that inherently rely on dominant solvation structures, preventing transformative progress in performance optimization^4,5. Here, we address this limitation through a delocalized electrolyte design that fosters a more disordered solvation microenvironment, thereby mitigating dynamic barriers and stabilizing interphases. The resulting delocalized electrolyte delivers notable energy densities of 604.2 Wh kg^-1 in a 5.5-Ah LiNi_0.9Co_0.05Mn_0.05O₂ (Ni90)||Li pouch cell with a lean electrolyte design (1.0 g Ah^-1) and 618.2 Wh kg^-1 in a 5.2-Ah Ni90||Li pouch cell with an ultralean electrolyte design (0.9 g Ah^-1), maintaining significant cycle stability over 100 and 90 cycles, respectively. In addition, the 70-104 V NCM811||Li battery pack (3,904 Wh) exhibits a high energy density of 480.9 Wh kg^-1 and stable cycling over 25 cycles. These results demonstrate the need to circumvent inherent reliance on dominant solvation structures in electrolyte design to achieve the high-energy Battery600 and scalable Pack480 targets.