Conformal Prelithiation Nanoshell on LiCoO Enabling High-Energy Lithium-Ion Batteries.

The initial lithium loss in lithium-ion batteries (LIBs) reduces their energy density (e.g., 15% or higher for LIBs using a Si-based anode). Herein, we report chemical formation of a conformal LiO/Co nanoshell (∼20 nm) on LiCoO particles as a high-capacity built-in prelithiation reagent to compensate this initial lithium loss. We show a 15 mAh g increase in overall charge capacity for the LiCoO with 1.5 wt % LiO/Co in comparison to the pristine LiCoO in virtue of the irreversible lithium extraction from the nanoshell (4LiO + 3Co → 8Li + 8e + CoO, 2LiO → 4Li + 4e + O↑). Paired with a graphite-SiO anode, a full cell using such a LiCoO cathode demonstrates 11% higher discharge capacity (2.60 mAh cm) than that using pristine LiCoO (2.34 mAh cm) at 0.1 , as well as stable battery cycling. Moreover, the prelithiated LiCoO is compatible with the current battery fabrication process.