Engineering

Faraday efficiency

Endocrinology

Physical chemistry

Solvation

Nanotechnology

Electrode

Diluent

Organic chemistry

Chemistry

Materials science

Cathodic protection

Lithium (medication)

Solvent

Lithium metal

Chemical engineering

Cathode

Metal

Electrolyte

Medicine

Anode

Chem

The stability of localized high-concentrated electrolytes (LHCEs) on the Li metal anode has been well established, but the understanding of its oxidation chemistry for high-voltage cathodes is unclear. Here, we demonstrate that the de-coordination between Li+ and solvents defines the anodic stability of LHCEs, which can be finely tuned by the ambient diluents. After screening the possible diluents, we found that 2H,3H-decafluoropentane (HFC) satisfies the principle of relatively weak but sufficient interactions with solvation shell, thus strengthening the Li+ coordination and offering electrolytes excellent antioxidant chemistry. The proposed HFC-LHCE enables practical Li metal batteries to realize >90% capacity retention with a Coulombic efficiency of 99.91% for >180 cycles under aggressive conditions (4.4 V 20-μm-Li||3.7-mAh cm−2-LiNi0.8Mn0.1Co0.1O2 and 4.5 V 20-μm-Li||4-mAh cm−2-LiCoO2 cells). This work presents guiding principles for improving electrolyte cathodic and anodic stability, which benefits the development of LHCEs and inspires the formulation of next-generation lithium batteries.

Deciphering and modulating energetics of solvation structure enables aggressive high-voltage chemistry of Li metal batteries