Bimetal/Li2Se Nanocomposite as Cathode Prelithiation Additive for Sustainable High-Energy Lithium-Ion Batteries

Cathodes undergo unavoidable lithium loss due to the formation of a solid electrolyte interface (SEI), which seriously affects the energy density of lithium iron phosphate (LFP) batteries. To compensate for the initial capacity loss, we introduced an NiCo-Li2Se nanocomposite to an LFP battery system to act as a competitive cathode prelithiation additive. Benefiting from its zero gas-emissions, ambient stability, high irreversible capacity, low delithiation potential, and good compatibility with carbonate-based electrolytes, the NiCo-Li2Se additive based on the chemical conversion reaction effectively offset the initial lithium loss. As a result, with 10 wt% addition, the initial charge capacity of the Li||LFP half-cell was improved by 34 mA h g−1. The Gra||LFP-Li2Se full-cell released an initial discharge specific capacity of 159.7 mA h g−1, which increased by 18% compared with the Gra||LFP full-cell, resulting in improved cycling stability. In addition, COMSOL Multiphysics simulation was applied to verify the function of the NiCo-Li2Se additive, and pouch cells were assembled to explore its potential in large-scale industrial application. This work provides a meaningful research direction for the design of a prelithiation additive for LFP cells.