Spent Li-ion batteries (LIBs) pollute the environment and endanger human health; however, they are valuable mineral resources . Here, we designed an extraction system composed of 0.4 mol/L 2-thenoyltrifluoroacetone (HTTA), 0.4 mol/L trioctylphosphine oxide (TOPO), and ionic liquid (IL) 1-Butyl-3-MethylImidazolium bis (trifluoromethyl sulfonyl) imide to recover valuable metals from spent LIBs. Under the optimum conditions (O/A = 1/1, 25 °C, reaction time 20 min, and pH = 3.65, the pH of the solution does not need to be adjusted), over 99.54% of Co, 99.85% of Mn, and 99.68% of Ni were extracted, while only 2.84% of Li were coextracted. The ultraviolet spectrum analysis showed that the spectral peaks of the stripping solution changed at 266 and 293 nm, indicating that CH 3 COO – participated in the extraction reaction. Following stripping with sulfuric acid , the pH of the solution was adjusted with 2.0 mol/L NaOH, and approximately 99% of the Al 3+ ions were precipitated. Nickel and manganese sulphates were added to the stripping solution. The precursor was prepared using a coprecipitation method. The precursor was then mixed with lithium hydroxide and calcined at 1000 °C for 12 h to obtain LiNi 1/3 Co 1/3 Mn 1/3 O 2 .
Ran Wang,Jinzhen Huang,Xinghong Zhang,Jiecai Han,Zhihua Zhang,Tangling Gao,Lingling Xu,Shengwei Liu,Ping Xu,Bo Song
Developing earth-abundant and highly effective electrocatalysts for hydrogen evolution reaction (HER) is a prerequisite for the upcoming hydrogen energy society. Two-dimensional (2D) high-entropy metal phosphorus trichalcogenides (MPCh3) have the advantages of both near-continuous adsorption energies of high-entropy alloys (HEAs) and large specific surface area of 2D materials, which are excellent catalytic platforms. As a typical 2D high-entropy catalyst, Co0.6(VMnNiZn)0.4PS3 nanosheets with high-concentration active sites are successfully demonstrated to show enhanced HER performance: an overpotential of 65.9 mV at a current density of 10 mA cm–2 and a Tafel slope of 65.5 mV dec–1. Decent spectroscopy characterizations are combined with density function theory analyses to show the scenario for the enhancement mechanism by a high-entropy strategy. The optimized S sites on the edge and P sites on the basal plane provide more active sites for hydrogen adsorption, and the introduced Mn sites boost water dissociation during the Volmer step. Two-dimensional high-entropy MPCh3 provides an avenue for the combination of HEAs and 2D materials to enhance the HER performance, which also provides an alternative materials platform to explore and design superior catalysts for various electrochemical systems.
Qin Wang,Yejian Xue,Shanshan Sun,Shanshan Yan,He Miao,Zhaoping Liu
Facile synthesis of high efficient bi-functional oxygen catalysts is important for large-scale application of rechargeable metal-air batteries . Herein, an ethanol-water mediated co-precipitation approach is applied to fabricate Co–Mn–Ni (CMN) ternary spinel oxides with uniform 1D structure. Their catalytic activities toward the oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) are investigated by the rotating ring-disk electrode (RRDE) techniques. The ternary spinel oxide with the Co/Mn/Ni atomic ratio of 2:3:1 (CMN-231) exhibits the best bi-functional activities among the as-prepared ternary, binary and unitary spinel oxides (△E is as low as 0.88 V), which can be attributed to its reasonable element composition , mesoporous nanorod structure, strong oxygen-adsorption ability and good charger-transfer capability. In addition, the CMN-231 catalyst demonstrates a strong stability during long-term operation. This well-designed catalyst is applied in a homemade zinc-air battery, and exhibits good charge–discharge performances (voltage gap is 0.9 V at 50 mA cm −2 ) and remarkable cycling stability.