Year: 2026
Type: article
Abstract: The development of safer and thermally robust electrolytes is essential for improving the reliability of lithium-ion batteries, particularly under demanding operating conditions. In this work, fluorine-free electrolytes based on diethyl adipate (DEA) in combination with lithium bis(oxalato)borate (LiBOB) were developed and evaluated in lithium nickel cobalt manganese oxide (NCM)/graphite lithium-ion cells. An optimal salt concentration of 0.7 molal (m) LiBOB was identified, while the addition of ethylene carbonate (EC) and propylene carbonate (PC) enhances ionic conductivity. Electrochemical testing revealed slightly lower initial capacities at low and moderate temperatures compared to the benchmark electrolyte LP40 (1 molar (M) lithium hexafluorophosphate (LiPF 6 ) in EC:diethyl carbonate (DEC) (1:1 by weight (wt))), but markedly improved capacity retention during long-term cycling. At 25 ∘ C, the LiBOB–DEA–EC system retained 85.1% of its initial capacity after 965 cycles, compared to 71.4% for LP40, with further improvements at elevated temperatures (40 ∘ C–70 ∘ C), where LiBOB–DEA-based systems showed reduced degradation and no premature cell failure. In addition, the developed electrolytes exhibited substantially improved safety characteristics, including high flash points of 125 ∘ C–132 ∘ C for the DEA-based solvent mixtures and a delayed onset of exothermic reactions in heat-wait-seek tests. Overall, the results demonstrate the potential of LiBOB–DEA-based electrolytes as a promising approach toward safer and more thermally stable lithium-ion batteries.
Language: English
Subfield: Electrical and Electronic Engineering
Field: Engineering
Domain: Physical Sciences
Open Access status: hybrid
Estimated APC paid: $1,950
OpenAlex ID: W7220469217