Core Solvents for High-Voltage Electrolytes (II) | Practical Application & Selection Guide for Linear Fluorinated Carbonates

I. Practical Battery Application Performance of Three Linear Fluorinated Carbonates

1. Compatibility with Various High-Voltage Battery Systems

The following table summarizes real-world application cases of three linear fluorinated carbonates across mainstream high-voltage battery systems, covering ternary (NCM), spinel lithium nickel manganese oxide (LNMO), lithium-rich manganese-based (LMNC), lithium cobalt oxide (LCO) and other battery systems, with cut-off voltages ranging from 4.25V to 4.95V, fully demonstrating the broad high-voltage adaptability of fluorinated carbonates.

The data above shows that all three linear fluorinated carbonates demonstrate excellent high-voltage adaptability across different battery systems. Specifically, , FEMC exhibits favorable high-temperature cycling stability in NCM622 and NCM811 ternary systems; FDEC in LNMO (lithium nickel manganese oxide) and LMNC (lithium-rich manganese-based) ultra-high-voltage systems shows significant advantages with optimal capacity retention; while the FEC/FDEC co-formulation system enables substantial improvements in low-temperature and rate performance for silicon-based anode batteries.

2. Significantly Enhanced Flame-Retardant Safety

The -CF₃ functional groups can scavenge combustion free radicals and suppress sustained flame propagation. The self-extinguishing time (SET) provides an intuitive metric for comparison.

The data shows that conventional EC/EMC carbonate-based systems exhibit a self-extinguishing time as high as 60 s/g with a flash point of merely 28°C, posing significant safety hazards. By substituting conventional solvents with FEMC or FDEC, the SET drops to 0 s/g, achieving complete non-flammability. This property is of critical importance for thermal runaway prevention in power batteries.

II. Cost Analysis and Application Scenario Selection

1. Cost Differentiation

The cost differences among the three linear fluorinated carbonates primarily stem from fluoroalcohol raw material consumption, synthetic route complexity, and purification process difficulty.

2. Application Scenario Selection for Three Linear Fluorinated Carbonates

Considering high-voltage performance, low-temperature rate capability, flame-retardant safety, and cost factors collectively, the selection recommendations are as follows:

From a selection perspective, FDEC offers irreplaceable advantages in ultra-high-voltage (≥4.8V) long-cycle applications, while FEMC provides superior cost-effectiveness in low-temperature fast-charging and general-purpose high-voltage scenarios due to its lower viscosity and cost. In practical formulation development, FEMC and FDEC are frequently co-formulated to balance high-voltage stability with low-temperature performance while controlling overall cost.

III. Cheerchem’s High-Voltage Product Matrix

Driven by technological innovation as its core, Cheerchem has established a dual-track product strategy: on one hand, building a comprehensive fluorinated solvent R&D and mass-production platform, having independently developed multiple fluorinated electrolyte solvents including FEC, DFEC, FEMC, FEEC, and FDEC, with all products in stable large-scale production and capable of continuous high-volume supply; on the other hand, strategically deploying a high-voltage functional additive product line, forming a synergistic system of fluorinated solvents and high-voltage functional additives that comprehensively addresses the diverse electrolyte formulation needs for high-voltage batteries, low-temperature fast charging, and high-safety applications.

1. Fluorinated Solvent + High-Voltage Functional Additive Series

Cheerchem has established a complete product matrix covering both fluorinated solvents and high-voltage functional additives, with the following grade system:

Among these, Cheeradd 374 (FEMC), Cheeradd 418 (FEEC), Cheeradd 578 (FDEC) are the three linear fluorinated carbonate solvents analyzed in this article. Together with cyclic fluorinated solvents such as Cheeradd 218 (FEC) and Cheeradd 274 (DFEC), they constitute a complete fluorinated solvent product line. Additionally, high-voltage functional additives including MMDS, DTS, DENE, TMSB, TMSP, TMSPi, LiBOB, and LiDFOP are used synergistically with fluorinated solvents to form a complete high-voltage electrolyte raw material solution.

2. Applications of High-Voltage Functional Additives

The following table summarizes typical application formulations of Cheerchem’s high-voltage functional additives across different battery systems:

The application data shows that Cheeradd’s high-voltage functional additives cover a wide voltage range from 4.4V to 5.4V. Notably, TMSPi enables stable high-voltage operation at 5.0V in LNMO/C systems, while LiBOB supports up to 5.4V in LNMO/Li systems. These high-voltage additives effectively suppress oxidative decomposition of the electrolyte under high-voltage conditions and facilitate the formation of a stable cathode electrolyte interphase (CEI), thereby significantly improving battery cycling life and safety performance.

Conclusion

Through the systematic analysis in both Part I and Part II, we can clearly see the technical value of linear fluorinated carbonates as core solvents for high-voltage electrolytes:

From Structure to Performance: The introduction of fluorine atoms simultaneously lowers both HOMO and LUMO energy levels, enhancing cathode oxidation resistance while strengthening anode film-forming capability. The symmetrically difluorinated FDEC exhibits the best overall performance, while the asymmetrically monofluorinated FEMC offers advantages in low-temperature performance and cost.

From Laboratory to Application: All three linear fluorinated carbonates demonstrate excellent cycling stability across ternary, spinel lithium nickel manganese oxide, lithium-rich manganese-based, and silicon-based anode high-voltage battery systems, while achieving complete electrolyte non-flammability (SET=0), providing a fundamental safety guarantee for power batteries.

From Products to Solutions: Leveraging its complete fluorinated solvent product line and high-voltage functional additive matrix, Cheerchem provides customers with end-to-end electrolyte raw material solutions—from solvent selection to additive synergy matching—comprehensively serving the development needs of high-voltage ternary, high-voltage LCO, and other high-energy-density cells.