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.
The low solubility of CO2 molecules and the
competition
of the hydrogen evolution reaction (HER) in aqueous electrolytes pose
significant challenges to the current photoelectrochemical (PEC) CO2 reduction reaction. In this study, inspired by the bilayer
phospholipid molecular structure of cell membranes, we developed a
Cu2O/Sn photocathode that was modified with the bilayer
surfactant DHAB for achieving high CO2 permeability and
suppressed HER. The Cu2O/Sn/DHAB photocathode stabilizes
the *OCHO intermediate and facilitates the production of HCOOH. Our
findings show that the Faradaic efficiency (FE) of HCOOH by the Cu2O/Sn/DHAB photoelectrode is 83.3%, significantly higher than
that achieved with the Cu2O photoelectrode (FEHCOOH = 30.1%). Furthermore, the FEH2 produced by the Cu2O/Sn/DHAB photoelectrode is only 2.95% at −0.6 V vs
RHE. The generation rate of HCOOH by the Cu2O/Sn/DHAB photoelectrode
reaches 1.52 mmol·cm–2·h–1·L–1 at −0.7 V vs RHE. Our study provides
a novel approach for the design of efficient photocathodes for CO2 reduction.
The extensive use of lithium-ion batteries (LIBs) has caused environmental pollution and waste of resources. Developing sustainable recycling strategies for the cathode of spent LIBs can bring about resource conservation and environmental benefits. In this work, the in situ reconstruction and functional reuse of spent LiCoO 2 were realized through two steps of chemical delithiation and hydrogen treatment. The chemical delithiation promotes spent LiCoO 2 to form a 3D layered structure, exposing more active sites and increasing charge transfer. Thermal treatment of hydrogen induces LiCoO 2 transition to a lower valence state and forms more oxygen vacancies, which are more beneficial to the oxygen evolution reaction. Consequently, the Ar-H 2 -300 °C-delithiation from spent lithium cobalt oxide (DLSLCO) exhibits high catalytic oxygen evolution reaction (OER) performance with a low overpotential of 365 mV at 10 mA cm −2 and a small Tafel slope of 67 mV decade −1 , which is even comparable to that of the recovered or synthesized LiCoO 2 catalysts reported in other literature studies.
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