Capacity retention improvement of LiCoO2 cathodes via their laser-ablation-based nanodecoration by BaTiO3 nanoparticles

Abstract

We report on the pulsed-laser-deposition (PLD) based nanodecoration of LiCoO2 (LCO) with BaTiO3 (BTO) nanoparticles (NPs) aimed at increasing the density of dielectric-active material–electrolyte triple-phase interfaces (TPIs). The BTO-NPs were deposited onto LCO at different numbers of laser pulses (NLp) and two different schemes, namely, (i) BTO-NP deposition on the surface of the precast cathode (“2D-nanodecoration”) and (ii) BTO-NP decoration of LCO powder prior to its processing to form a working cathode (“3D-nanodecoration”). While the “2D-nanodecoration” mode was found to improve significantly the discharge capacity of the LCO cathodes (by ∼30 mAh/g for NLp ≥ 200), their capacity retention (CR) was modest. In contrast, the “3D-nanodecoration” scheme enabled not only the volumic nanodecoration of the LCO powder by BTO-NPs but also their subsequent annealing to improve their crystallinity. These 3D-nanodecorated LCO cathodes were found to exhibit significantly higher CR values. In particular, for NLp = 100 k, a CR (@10 °C) as high as 78% was achieved (∼47% higher than that of their sol–gel-processed cathode counterparts). Our results point out that three key ingredients (small BTO-NP size, high DTPI, and high dispersibility of NPs on LCO) should be combined to ensure a high CR of BTO-NP-decorated LCO cathodes.