Specific Electrolyte for High-Voltage Lithium-Ion Battery {≥4.5V LiCoO2 + Graphite}, 200 g/bottle, CHVLIBSELCOG

Operating a lithium-ion cell with a Lithium Cobalt Oxide (LiCoO2 / LCO) positive electrode charged to ~ 4.5 V paired with a Graphite (Gr) negative electrode unlocks high volumetric energy densities (~ 180-190 mAh/g practical LCO capacity). However, standard carbonate electrolytes (such as 1 M LiPF6 in EC/EMC) undergo aggressive oxidative decomposition at the high-potential LCO surface, causing severe cobalt dissolution, surface phase transitions, and gas evolution. To achieve stable cycling under these harsh conditions, advanced high-voltage electrolyte engineering relies on Localized High-Concentration Electrolytes (LHCE) or functionalized multi-additive carbonate systems designed to build a robust, inorganic-rich Cathode Electrolyte Interphase (CEI) and Solid Electrolyte Interphase (SEI).

The Localized High-Concentration Electrolyte (LHCE) Strategy: Primary Salt: 1.0 M to 1.2 M Lithium bis(fluorosulfonyl)imide (LiFSI) or LiPF6. Co-Solvent / Primary Complexing Matrix: Dimethyl Carbonate (DMC) or Ethyl Methyl Carbonate (EMC) with minimal Ethylene Carbonate (EC) to reduce parasitic oxidation. Inert Fluorinated Diluent: 1,2-bis(1,1,2,2-tetrafluoroethoxy)ethane (TFEE / HFE-578E) or 1,1,2,2-tetrafluoroethyl 2,2,2-trifluoroethyl ether (TTE) added in a high volume ratio (e.g., 1.2:2.8 salt-solvent complex to diluent). The diluent does not coordinate with Li+, forcing an anion-rich inner solvation sheath. Upon electrochemical formation, this yields an inorganic-rich CEI (packed with LiF and sulfur-oxygen species) that passivates the 4.5 V LCO surface against transition metal leaching and structural collapse.

If utilizing a conventional carbonate solvent framework for cost and viscosity optimization, a heavily additized standard formulation is required: Main Salt: 1.0 M LiPF6; Solvent Base: Ethylene Carbonate (EC) + Ethyl Methyl Carbonate (EMC) (3:7 by weight); Functional Additives: (i) 2.0 wt% Fluoroethylene Carbonate (FEC) that is essential for generating a protective, elastic SEI on the graphite anode and contributing to fluoride-based CEI stabilization. (ii) 1.0wt% Lithium difluoro(oxalato)borate (LiDFOB) or LiBOB: Forms a stable boron- and oxalate-based passivating film on the 4.5 V LCO cathode, suppressing oxygen release from the lattice. (iii) 0.5wt% Tris(trimethylsilyl) phosphite (TMSPi): Scavenges trace HF and moisture, preventing acid-catalyzed dissolution of cobalt.

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

References: 

1. C. Yang, et al. A Safe Electrolyte Enriched with Flame-Retardant Solvents for High-Voltage LiCoO2||Graphite Pouch Cells, ACS Energy Lett. (2024) 9 (11): 5364–5372.
2. H. You, et al. Weakened Solvation Structure Electrolytes Enable High-Voltage Graphite||LiCoO2 Batteries, ACS Appl. Energy Mater. (2024) 7 (15): 6696–6703.