Porosification and Fe³⁺ Intercalation of Spent LiCoO₂ as an Efficient Oxygen Evolution Electrocatalyst

Abstract

Lots of spent Li-ion batteries have caused waste of mineral resources and environmental pollution. However, it is extremely challenging to develop more efficient recycling methods. Therefore, in this paper, the reconstitution of spent lithium cobalt oxides (LiCoO2) was achieved by delithiation and iron intercalation in an aqueous two-electrode system, which was used for the oxygen evolution reaction. The electrochemical deintercalation of Li+ promoted the formation of 3D porous LiCoO2, which exposed more active sites in contact with the electrolyte. The intercalation of Fe3+ increased the conductivity of LiCoO2 and introduced Fe3+ active sites, which were more favorable for the oxygen evolution reaction. As a result, the reconstituted Fe 0.5 h-SLCO with an intercalation time of 0.5 h exhibited an overpotential of 325 mV at a current density of 10 mA cm−2 and a Tafel slope of 57 mV decade–1 in 1 M KOH, which was even more excellent than part of synthesized LiCoO2-based catalysts reported in other literature.

Hydrogen-Treated Spent Lithium Cobalt Oxide as an Efficient Electrocatalyst for Oxygen Evolution

“…However, by controlling the delithiation time, half of the lithium is still used to maintain the original layered structure, which contributes more favorable conditions for the OER. 25 The DLSLCO was further heat-treated with Ar/H 2 at different temperatures. The XRD patterns of heat-treated samples are displayed in Figure 2.…”

“…This is due to the fact that the closely stacked layers of LiCoO 2 are destroyed after delithiation. However, by controlling the delithiation time, half of the lithium is still used to maintain the original layered structure, which contributes more favorable conditions for the OER …”

Degradation Mechanisms of Electrodes Promotes Direct Regeneration of Spent Li‐Ion Batteries: A Review

“…Zhang et al demonstrated the Co 3 O 4 phase formed on the surface (Figure 4a) of LCO during cycling at the atomic level by transmission electron microscopy (TEM), [66] which is con-firmed by the XRD and Raman results. Li and Wang et al found that there were obvious cracks and holes on the surface and inside (Figure 4b,c) of the spent LCO, [65,67] which formed due to stress concentration during cycling. The formation of Li vacancies in LCO is accompanied by vigorous Li + deintercalation and The XRD patterns of spent LCO and regenerated LCO with different regenerated conditions.…”

“…Li and Wang et al. found that there were obvious cracks and holes on the surface and inside (Figure 4b,c) of the spent LCO, [ 65,67 ] which formed due to stress concentration during cycling. The formation of Li vacancies in LCO is accompanied by vigorous Li + deintercalation and intercalation, causing uneven stress distribution in the LCO lattice structure, was proved by continuous changes of diffraction peak around 19° in the XRD pattern upon cycling.…”

“…b) SEM images of spent LCO (scale bar, 2 μm). Reproduced with permission [67]. Copyright 2020, American Chemical Society.…”