Construction of highly stable LiI/LiBr-based nanocomposite cathode via triple confinement mechanisms for lithium-halogen batteries

Abstract

Lithium-halogen batteries (LHBs), including lithium iodide (Li-I2) and lithium bromide (Li-Br2) batteries, are receiving more attention for offering high energy density and excellent kinetic performance. However, LHBs commercialization is seriously hindered by the high solubility of halides, causing lower capacity and poor cyclability. This research covers the fabrication of a highly stable cathode of amorphous carbon coated CMK-3/LiI/LiBr nanocomposite for metal lithium batteries. The nanopores and coated layer can physically trap the dissolution of active materials. The amorphous carbon generated from polyacrylonitrile carries abundant nitrogen heteroatoms for the stable anchorage of halogens and halides via strong chemical adsorption. In addition, iodine can act as a complexing agent with bromine to reduce solvation energy. Consequently, the as-prepared CMK-3/LiI/LiBr/carbon (CIBP) nanocomposite cathode demonstrates an ultra-high reversible capacity of 407.4 mAh/g at the current density of 1.0 C performing up to 300 stable cycles.