Inactive components and safety hazards are two critical challenges in realizing high-energy lithium-ion batteries. Metal foil current collectors with high density are typically an integrated part of lithium-ion batteries yet deliver no capacity. Meanwhile, high-energy batteries can entail increased fire safety issues. Here we report a composite current collector design that simultaneously minimizes the ‘dead weight’ within the cell and improves fire safety. An ultralight polyimide-based current collector (9 μm thick, specific mass 1.54 mg cm−2) is prepared by sandwiching a polyimide embedded with triphenyl phosphate flame retardant between two superthin Cu layers (~500 nm). Compared to lithium-ion batteries assembled with the thinnest commercial metal foil current collectors (~6 µm), batteries equipped with our composite current collectors can realize a 16–26% improvement in specific energy and rapidly self-extinguish fires under extreme conditions such as short circuits and thermal runaway.
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This work was supported by the Assistant Secretary for Energy Efficiency and Renewable Energy, Office of Vehicle Technologies of the US Department of Energy under the eXtreme Fast Charge Cell Evaluation of Li-ion batteries (XCEL) program. We thank the Stanford Nano Shared Facilities (SNSF) and the Stanford Nanofabrication Facility (SNF) for SEM, FTIR, XPS, tensile strength characterizations and Lesker sputter fabrication.
The authors declare no competing interests.
Publisher’s note Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.
Supplementary Figs. 1–16 and Tables 1–14.
Tape peel testing of PI-TPP-based CC.
Flame retardancy test of Gr-coated Cu foil CC with electrolyte.
Flame retardancy test of Gr-coated PI-Cu CC with electrolyte.
Flame retardancy test of Gr-coated PI-TPP-Cu CC with electrolyte.
Flame retardancy test of LCO-Gr full cell based on commercial Al||Cu CC with electrolyte.
Flame retardancy test of LCO-Gr full cell based on PI-TPP-Al||PI-TPP-Cu CC with electrolyte.
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Ye, Y., Chou, LY., Liu, Y. et al. Ultralight and fire-extinguishing current collectors for high-energy and high-safety lithium-ion batteries. Nat Energy 5, 786–793 (2020). https://doi.org/10.1038/s41560-020-00702-8
Nature Energy (2020)