Physics

Nanotechnology

Electrode

Organic chemistry

Lithium metal

Engineering physics

Endocrinology

Engineering

Physical chemistry

Ionic bonding

Inorganic chemistry

Chemistry

Materials science

Carbonate

Lithium (medication)

Metal

Lithium carbonate

Electrolyte

Energy density

Chemical engineering

Medicine

iScience

Coupling thin Li metal anodes with high-capacity/high-voltage cathodes such as LiNi0.8Co0.1Mn0.1O2 (NCM811) is a promising way to increase lithium battery energy density. Yet, the realization of high-performance full cells remains a formidable challenge. Here, we demonstrate a new class of highly coordinated, nonflammable carbonate electrolytes based on lithium bis(fluorosulfonyl)imide (LiFSI) in propylene carbonate/fluoroethylene carbonate mixtures. Utilizing an optimal salt concentration (4 M LiFSI) of the electrolyte results in a unique coordination structure of Li+-FSI−-solvent cluster, which is critical for enabling the formation of stable interfaces on both the thin Li metal anode and high-voltage NCM811 cathode. Under highly demanding cell configuration and operating conditions (Li metal anode = 35 μm, areal capacity/charge voltage of NCM811 cathode = 4.8 mAh cm−2/4.6 V, and anode excess capacity [relative to the cathode] = 0.83), the Li metal-based full cell provides exceptional electrochemical performance (energy densities = 679 Wh kgcell−1/1,024 Wh Lcell−1) coupled with nonflammability.

Nonflammable Lithium Metal Full Cells with Ultra-high Energy Density Based on Coordinated Carbonate Electrolytes