A multi-dimensional collaborative strategy for developing low-temperature and high-voltage resistant electrolytes

Abstract

Conventional lithium-ion batteries suffer from impaired charge transfer kinetics due to high viscosity and low conductivity at low temperatures, alongside performance degradation, which restricts their applications in polar exploration and aerospace engineering. To address these challenges, we engineered a dual-salt electrolyte through solvent-salt-additive triple synergy. This system employs a LiPF₆/LiFSI dual-salt electrolyte system, where the synergistic interaction between the two lithium salts optimizes electrode interfacial compatibility and ion transport kinetics. The solvent matrix is composed of EC (high dielectric constant medium), ethyl methyl carbonate (EMC, wide electrochemical stability window), and propyl acetate (PA, low freezing point), forming a functionalized composite solvent system. The incorporation of film-forming additives facilitates the formation of a dense and stable solid electrolyte interphase (SEI). Through this coordinated design, simultaneous enhancement of interfacial stability and lithium-ion migration kinetics is achieved. Consequently, the conductivity of this electrolyte is greater than 1 mS·cm⁻¹ at -50 ℃. The LiCoO₂/graphite lithium-ion battery employing this electrolyte exhibits outstanding performance: > 80% capacity retention relative to room-temperature capacity at -60 ℃ (0.5C); > 80% capacity retention after 100 cycles at -40 ℃; and ~ 98% capacity retention after 50 cycles at 50 ℃ (0.5C).

Graphical abstract