Research Results
Recyclable deep eutectic solvents support NCA cathodes recycling: green solvent utilization and selective metal recovery
Main Authors
Ching-Lung Chen, Shuo-Xuan Zhou, PratimaDevi Sivasubramanian / MCUT
Abstract & Objective
The quick progress of the electric vehicle industry has led to a non-uniform distribution of used lithium-ion batteries, emphasizing the immediate requirement for sustainable techniques to recycle batteries. Classical hydrometallurgical techniques, however, are effective, depend completely on robust acids and lead to challenges of secondary contamination, demanding the advancement of sustainable choice. In this research, a type III deep eutectic solvents (DES), obtained from choline chloride and oxalic acid dihydrate, was utilized to facilitate a closed-loop recycling methodology for ternary NCA (LiNi₀.₈Co₀.₁₅Al₀.₀₅O₂) cathodes. Oxalic acid performed as a leaching medium that also enabled the preferential precipitation of nickel as nickel oxalate. Under ideal conditions of 1:1 M DES ratio, 10 gL⁻¹ solid liquid ratio, and 110 °C for 8 h, nickel was selectively precipitated as pristine nickel oxalate, validated via XRD. Improved leaching efficacies were maintained in the residual solution for lithium (100%), cobalt (76%), and aluminium (62.5%). Consecutive separation was attained by regulating solution chemistry: cobalt was precipitated as cobalt oxalate via coordination tuning, subsequently by aluminium precipitation as hydroxide through pH adjustment. This serial technique indicates selectivity and efficiency also reducing ecological impact, providing a renewable, feasible route for LIB metal recovery. The findings demonstrate the potential of DES-based techniques in developing circular economy principles for future generation battery recycling.
Graphical Abstract
Spin crossover-driven diiron electrocatalyst boosts sustainable water oxidation
Main Authors
Ching-Wei Tung, Wei Zhang, Tai Ying Lai, Jiali Wang, You-Chiuan Chu, Guan-Bo Wang, Chia-Shuo Hsu, Yen-Fa Liao, Nozomu Hiraoka, Hirofumi Ishii, Xiao Cheng Zeng & Hao Ming Chen
Abstract
Electrocatalytic reduction of carbon dioxide and water oxidation are promising technologies to mitigate environmental problems. A critical bottleneck, however, is the significant energy loss that arises from the anodic oxygen evolution reaction (OER) with its sluggish kinetics and reliance on scarce noble metals. It is therefore essential to develop earth-abundant and efficient OER catalysts. Here we report the reactive diiron electrocatalyst [Fe₂(µ-O)(µ-OH)(L1)₂], where L1 is a nitrogen-based ligand, which exhibits an outstanding performance—achieving a turnover frequency of 20.2 s⁻¹ at 1.580 V and a low overpotential of 184 mV at a current density of 10 mA cm⁻²—and exceptional stability over 1,000 h. This diiron electrocatalyst is formed via a spin crossover-driven dimerization mechanism, where the resulting diiron atomic configuration promotes strong metal–ligand covalency and facilitates the formation of key intermediates that are essential for efficient OER catalysis. Our findings offer a promising strategy for the design of high-performance catalysts for water oxidation and sustainable electrocatalysis.
Graphical Abstract
Insight into the diurnal variations and potential sources of ambient PM2.5-bound polycyclic aromatic hydrocarbons during spring in Northern Taiwan
Authors
Yi-Wen Chen, Kuan-Ting Liu, Ho Thi Phuong Thao, Meng-Ying Jian, Yu-Hsiang Cheng*
Introduction & Objective
In recent decades, polycyclic aromatic hydrocarbons (PAHs), the primary organic pollutants associated with particulate matter (PM), have attracted significant attention due to their carcinogenic and mutagenic potential. However, past studies have lacked exploration into the diurnal variation characteristics of PAHs, primarily due to limited analytical technical capabilities. Therefore, this study aimed to investigate the diurnal variations, possible sources, and potential health risks associated with PM2.5-bound PAHs in northern Taiwan.
Graphical Abstract
