A.P. Zhang, E.D. Yang, Z.H. Bi, G.R. Wang, S.H. Liao, X.F. Li, Y. Yu *, Q. Liu *, X.H. Bao and Z.-S. Wu *

ACS Energy Letters, 2025, 10.

DOI: 10.1021/acsenergylett.4c03117 [PDF]

Elevating the charge cut-off voltage of LiCoO2 (LCO) from 4.4 to 4.7 V can significantly boost energy density. However, conventional electrolyte strategies encountering the viscosity and wettability obstacles for high-voltage LCO can’t tackle the issues of severe electrolyte decomposition, electrode-electrolyte interface degradation, and irreversible phase-transitions simultaneously. Herein, we achieved stable operation of commercial LCO at 4.7 V using a super-wettable low-concentration fluoroborate dual-salt electrolyte (LFE). Our elaborated LFE (0.5 M) features anion-enrich solvation structure that creates ultrathin, stable yet fast ion/electron transfer electrode/electrolyte interphases, significantly alleviating electrolyte decomposition, interface degradation, and injurious lithium dendrites. Consequently, LFE enables LCO to deliver a record capacity retention of 89.5% after 200 cycles and rate capability, far surpassing the state-of-the-art 4.7 V-charged Li||LCO batteries. We assembled 1.25 Ah-class graphite||LCO pouch cell using LFE offering 100% capacity retention after 300 cycles, showcasing practicality. This work inaugurates an innovative pathway to maximize energy storage devices performance.