Specific Electrolyte for High-Voltage Lithium-Ion Battery {≥4.4V LiCoO2 + Si/C, Si≤20%}, 200 g/bottle, CHVLIBSELCOSiC

Pairing a high-voltage Lithium Cobalt Oxide (LiCoO2 / LCO) cathode charged to ~ 4.4 V–4.5 V with a Silicon-Carbon (Si/C, 20 wt% silicon content) composite anode creates severe dual-interface challenges. The high-potential LCO requires an electrolyte with strong oxidation resistance to suppress cobalt dissolution and lattice oxygen release, while the silicon component demands a robust, elastic passivating layer to accommodate large volume fluctuations (~ 250-300%) and prevent continuous electrolyte consumption.

The recommended electrolyte recipe are shown below: (1) Salt Framework: 1.2 M dual-salt composition consisting of 1.0 M LiPF6 + 0.2 M Lithium bis(fluorosulfonyl)imide (LiFSI). LiPF6 ensures effective passivation of aluminum current collectors at high potentials, while the minor LiFSI component facilitates the rapid generation of an inorganic-rich, flexible fluoride layer essential for stabilizing the volume-changing silicon surface. (2) Solvent Architecture: (i) Core Solvents: Ethylene Carbonate (EC) + Diethyl Carbonate (DEC) + Fluoroethylene Carbonate (FEC) balanced to minimize gas evolution while maintaining high ionic conductivity. A typical optimized ratio is EC:DEC = 3:7 by weight supplemented by high-concentration functional co-solvents. (ii) Localized High-Concentration (LHCE) Alternative: For ultra-stable high-voltage cycling, a localized high-concentration matrix utilizing a fluorinated ether diluent (such as TTE or TFEE) helps lock down solvent reactivity against both the 4.4 V+ LCO surface and the lithiated silicon matrix. (3) Essential Functional Interphase Additives: (i) 5.0 wt% Fluoroethylene Carbonate (FEC): Non-negotiable for silicon-composite anodes; acts as the primary reductive precursor to build a dense, elastic, LiF-rich Solid Electrolyte Interphase (SEI) that accommodates particle breathing. (ii) 1.5 wt% Lithium difluoro(oxalato)borate (LiDFOB) or LiBOB: Forms a protective boron- and oxalate-based passivating film on the high-voltage LCO surface (forming a stable Cathode Electrolyte Interphase / CEI) to mitigate transition metal leaching. (iii) 1.0 wt% Vinylene Carbonate (VC) or Succinonitrile (SN): Works synergistically with FEC to optimize interfacial resistance and reduce gas generation during initial formation cycles.

Notes: Please store the specific LIB electrolyte in the glovebox due to its sensitivity to humidity.

References: 

1. Z. Sun, et al. Unraveling degradation mechanism of electrolyte at high voltage and a hybridization strategy for non-flammable 4.8 V LiCoO2 battery, Joule, 2025, 9, 102166
2. H. Yang, et al. Simultaneous enhancement of cathode and anode interfacial stability in high-voltage LiCoO₂–Si/C batteries through a hydrogen-free multi-cyano ligand inorganic salt electrolyte additive, Energy Storage Materials, 2025, 83,104703