A low-concentration sulfone electrolyte enables high-voltage chemistry of lithium-ion batteries

Abstract

Commercial carbonate electrolytes with poor oxidation stability and high flammability limit the operating voltage of Li-ion batteries (LIBs) to ~4.3 V. As one of the most promising candidates for electrolyte solvents, sulfolane (SL) has received significant interest because of its wide electrochemical window, low flammability and high dielectric permittivity. Unfortunately, SL-based electrolytes with normal concentrations cannot achieve highly reversible Li+ intercalation/deintercalation in graphite anodes due to an ineffective solid electrolyte interface, thus undermining their potential application in LIBs. Here, a low-concentration SL-based electrolyte (LSLE) is developed for high-voltage graphite||LiNi0.8Co0.1Mn0.1O2 (NCM811) full cells. A highly reversible graphite anode can be achieved through the preferential decomposition of the dual-salt LiDFOB-LiBF4 in the LSLE. The addition of fluorobenzene further restrains the decomposition of SL, endowing uniform, robust and inorganic-rich interphases on the electrode surfaces. As a result, the LSLE with improved thermal stability can support the MCMB||NCM811 full cells at 4.4 V, evidenced by an excellent cycling performance with capacity retentions of 83% after 500 cycles at 25 ℃ and 82% after 400 cycles at 60 ℃. We believe that the design of this fluorobenzene-containing LSLE offers an effective routine for next-generation low-cost and safe electrolytes for high-voltage LIBs.

Sulfur Solutions: Advancing High Voltage and High Energy Lithium Batteries with Organosulfur Electrolytes

“…However, the wettability of the system toward different cell components enhanced significantly with the addition of TTE. The group also utilized 17 O NMR to track the interaction through line shapes and chemical shifts and paired the result with AIMD simulations to gain insight into the concentration-dependent intermolecular solvation interactions. As the concentration of LiFSI in TMS goes up, the degree of coordination and complexation of the salt and solvent also increases, evidenced by the upfield chemical shifts of the sulfonyl group as it coordinates with lithium cations.…”

“…d) Cycling performance comparison of diluted 0.8 m LiDFOB‐0.2 m LiBF 4 in SL:FB compared to a 0.8 m LiDFOB‐0.2 m LiBF 4 in SL or a 1 m LiPF 6 in EC:EMC baseline electrolyte. [ 17 ] Reproduced with permission. [ 17 ] Copyright 2022, OAE Publishing.…”

“…This can result in the formation of thick, carbonaceous Solid Electrolyte Interfaces (SEI). [15][16][17][18] Additionally, functionalizing the sulfone backbone may lower the Lowest Unoccupied Molecular Orbital (LUMO) of the entire molecule, rendering the structure more susceptible to mass reduction. [8] To mitigate the degradation of organosulfur solvents, either synthetically modified or commercial sulfones are often blended with commercial co-solvents that promote SEI formation, salts, or protective additives.…”

Electrolyte Engineering Toward High Performance High Nickel (Ni ≥ 80%) Lithium‐Ion Batteries

“…[108] Another class of novel electrolytes is formulated by non-LiPF 6 salts (such as LiFSI, LiTFSI, and LiDFOB) and high-voltage stable solvents with different functional groups (Table 2). [110][111][112][113][114][115] Fan et al formulate a novel electrolyte consisting of 1.6 m LiFSI and (2-cyanoethyl)triethoxysilane (TEOSCN), possessing a self-purifying feature by scavenging unfavorable H + containing species (such as HF and H 2 O) and plus the efficient SEI/CEI forming capability (Figure 9a). [110] As a result, the asfabricated self-purifying electrolyte enables NCM811/MCMB full cells with an ultrahigh capacity retention of 81% at 60 °C.…”

Recent Advances in Electrolytes for Potassium‐Ion Batteries

“…[ 4–9 ] Nevertheless, LIBs fail to meet the requirements of large‐scale energy storage because of the scarcity and high price of lithium, cobalt, and nickel—the necessary elements for LIB manufacturing. [ 10–12 ] Therefore, new secondary batteries are in high demand to replace LIBs.…”