The leaching and recycling of valuable metals via environmentally benign solvents is important because of the everincreasing waste lithium-ion batteries, but it remains a challenge. Herein, a multi-functional deep eutectic solvent (DES) based on lactic acid (LA) and guanidine hydrochloride (GHC) was used to extract cobalt and lithium ions from LiCoO 2 . Due to the strong acidity (protons) and abundant chlorine coordinating ions of LA/GHC, the solubility of LiCoO 2 in LA/GHC could reach as high as 19.9 mg g À 1 (stirred at 80 °C for 24 h), and a little LiCoO 2 powder even could be dissolved at room temperature without stirring. Oxalic acid was used to strip and separate the oxalates of cobalt and lithium. Furthermore, LA/ GHC could be recycled with a similar dissolving performance. This work avoided using corrosive acids and could be realized at low temperature (80 °C), making it energy-saving and costeffective. It shows DESs have great potential in extracting strategically important metals from LiCoO 2 cathodes and provides an efficient and green alternative for sustainable recycling of spent lithium-ion batteries.

Ultrasonic irradiation drives the reduction of Pt4+ and tight adherence of the resulting metallic Pt nanoparticles to CdS to boost photocatalytic H2 evolution.

Visible light driven transformation of biomass to high-valued chemicals is attractive for achieving a low-carbon society. The solar-catalyzed oxidation of 5-hydroxymethylfurfural (HMF) to 2,5-diformylfuran (DFF) has great industrial potential because...

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