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

Abstract

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.

Recycling valuable materials from the spent lithium ion batteries to catalysts: methods, applications, and characterization

“…Upon careful optimization of the degradation conditions, a high LFX removal rate of 94% was achieved. Hossain et al developed thermally isolation and controlled recycling methods for selectively regenerating spent LiCoO 2 cathodes [43] . Through this process, they transformed the LiCoO 2 into porous Co 3 O 4 catalysts characterized by nanoscale grains and a substantial specific surface area.…”

Thermally Labile Organic-Soluble Heterometal Diorganophosphate-Derived Efficient Electrocatalysts for the Oxygen Evolution Reaction

“…Although olivine LiCoPO 4 has been synthesized and modified through several methods, the synthesis of metastable polymorphs is limited to kinetically controlled low-temperature methods such as traditional solvothermal or microwave-assisted solvothermal methods except Cmcm -LiCoPO 4 which was first prepared by a high-temperature and high-pressure solid-state route (Table S2). Additionally, the nonstoichiometric lithium-deficient TMPs and oxides are usually synthesized by electrochemical or chemical delithiation. ,− A direct synthesis route was later presented for the synthesis of Li-deficient Cmcm -Li 0.5‑δ CoPO 4 by a soft-chemical polyol approach . Subsequently, synthesis of substoichiometric lithium Li 1– x Co y Fe 1– y PO 4 /rGO was achieved by a nonaqueous sol–gel microwave reaction …”