Details

Autor(en) / Beteiligte

• Yang, Ruying
• Zhu, Nengwu
• Xi, Yunhao
• Gao, Sunjuanzi
• Wu, Pingxiao
• Dang, Zhi

Titel

Recovery of crystalline silicon from waste solar cells by a green deep eutectic solvent-hydrogen peroxide system

Ist Teil von

• Green chemistry : an international journal and green chemistry resource : GC, 2024-06, Vol.26 (12), p.7246-7257

Ort / Verlag

Cambridge: Royal Society of Chemistry

Erscheinungsjahr

2024

Quelle

Alma/SFX Local Collection

Beschreibungen/Notizen

• With the rise in installed capacity of photovoltaic systems, the growing generation of waste crystalline silicon solar cells has become an important issue. Silicon is one of the most valuable materials in cells; recyclable treatments with green techniques must be developed for it. A new strategy for the recovery of silicon wafers has been proposed using choline chloride and oxalic acid-based deep eutectic solvent-hydrogen peroxide (DES-H 2 O 2 ) aqueous solution systems. With the synergistic effect of DES and H 2 O 2 , the leaching efficiency of silver from cells reached 89.19%, along with complete aluminum leaching. Compared with only the DES control, the leaching efficiency of silver was enhanced by as high as 97.45%. Subsequently, reusable silicon wafers were obtained with 97.47 wt% surface purity, and 99.41% of silicon retention rate (169 μm) after removing Si 3 N 4 . Favorable results were mainly attributed to the higher concentration of H + due to a boost by oxalic acid-based DES compared to concentrations in an oxalic acid aqueous solution, which could provide stronger oxidizing power, and besides, lower oxidation activation energy for silver in H 2 O 2 . In this work, high-purity silicon wafers were obtained with high leaching efficiency of metals in a short time (2 h) at a low temperature (80 °C) without using strong acids; among solvents, the DES showed great potential for reuse. It is concluded that the DES-H 2 O 2 aqueous solution system provides an environmentally friendly process for green and nearly lossless recovery of silicon wafers from silicon solar cells. A new ChCl-OA-H 2 O 2 strategy was proposed to recover silicon from solar cells with high metal leaching efficiency with higher acidity and lower activation energy, which provided purity and retention rate for Si of 97.47 and 99.41%, respectively.