The Fluorine‐Rich Electrolyte as an Interface Modifier to Stabilize Lithium Metal Battery at Ultra‐Low Temperature

Abstract

Lithium (Li) metal batteries (LMBs) are still limited by lithium dendrite growth and solvated structure at low temperatures. A stable solid electrolyte interface (SEI) and solvent sheath structure are the future directions of liquid metal battery development. However, most artificial SEIs and electrolytes cannot meet the original objective of high conductivity and low nucleation potential multifunctional design. To address this challenge, an electrolyte with excellent high current density and low‐temperature performance is reported here. In this electrolyte environment, the thickness and microstructure of the “Chain Link Ships” SEI are formed. Moreover, the additives improve the desolvation ability of Li+ in the ester electrolytes. Under the harsh environment (−30 °C), the average coulombic efficiency (CE) of the Li||copper (Cu) battery reaches 98% after 200 cycles. Even at −40 °C, the Li||LiFePO4 (LFP) battery shows 90% capacity retention after 100 cycles at the cathode‐limited areal capacity (5 mAh cm−2). Furthermore, at 30 °C, the Li||LFP battery can cycle stably for 1200 cycles at 5 C, and the capacity retention reaches 93.5%. This addition strategy provides insights into the commercial application of new solvated structure electrolytes and a new approach for commercial low‐temperature LMBs.

Promoting the Normal- and Low-Temperature Performances of Natural Graphite by the F-Doping Derived from PVDF Modification

“…The Li x PO y F z and chemisorbed fluorine were distinguished only on the anode surface and were absent after etching, so they were caused by the contact with trace water in the measurement. 22,29,30 The XPS data after etching confirmed that the main inorganic ingredients of Li 2 CO 3 , Li 2 O, and LiF are close for the NG and PG180-1 anodes. Owing to the low addition of PVDF modifier and the coexistence of F-containing binder of PVDF and electrolyte of LiPF 6 , the difference in XPS information obtained from the NG and PG180-1 anodes is not unambiguous, so other techniques were adopted to reveal the modification mechanism.…”

“…The surface SEI mainly contains Li 2 CO 3 (Li 1s at 55.4 eV and O 1s at 531.7 eV , ), Li x PO y F z (F 1s at 687 eV, O 1s at 534.0 eV, and Li 1s at 56.0 eV − ), traces of LiF (F 1s at 686.5 eV and Li 1s at 57.0 eV − ), and chemisorbed fluorine (F 1s at 684.68 eV), while the etched surface is dominantly comprised of LiF, a minute amount of Li 2 O (Li 1s at 55.6 eV and O 1s at 529.8 eV , ), and Li 2 CO 3 . The Li x PO y F z and chemisorbed fluorine were distinguished only on the anode surface and were absent after etching, so they were caused by the contact with trace water in the measurement. ,, The XPS data after etching confirmed that the main inorganic ingredients of Li 2 CO 3 , Li 2 O, and LiF are close for the NG and PG180-1 anodes. Owing to the low addition of PVDF modifier and the coexistence of F-containing binder of PVDF and electrolyte of LiPF 6 , the difference in XPS information obtained from the NG and PG180-1 anodes is not unambiguous, so other techniques were adopted to reveal the modification mechanism.…”

Developing a nitrile-based lithium-conducting electrolyte for low temperature operation

“…25 For batteries equipped with lithium metal anodes, stable cycling ranging between À40 C to even À85 C has been achieved by leveraging unique combinations of uorinated electrolytes. 26,27 These results highlight the need for discovering new solvents or solvent combinations that can provide high dielectric permittivity, low dynamic viscosity, and interface stabilizing properties.…”

Nitrogen‐doped Porous Carbon Nanofibers Decorated with Nickel Nanoparticles for Unlocking Low‐cost Structural Lithium Metal Anodes

“…Dendrites can pierce the separator, causing several safety issues such as short circuit, thermal runaway and explosion. [19][20][21][22][23][24] To address the problem of lithium dendrite growth, researchers have pioneered several strategies to stabilize lithium metal anodes, such as constructing artificial solid electrolyte interface (SEI) films, [25][26][27] electrolyte optimization, [28][29][30][31][32][33] and designing structural lithium metal anode hosts. [34][35][36][37][38][39][40][41] The first two methods can inhibit the growth of lithium dendrites to a certain extent.…”

“…To address the problem of lithium dendrite growth, researchers have pioneered several strategies to stabilize lithium metal anodes, such as constructing artificial solid electrolyte interface (SEI) films, [25–27] electrolyte optimization, [28–33] and designing structural lithium metal anode hosts [34–41] . The first two methods can inhibit the growth of lithium dendrites to a certain extent.…”