Sustainable Development Goals
Abstract/Objectives
Solar power generation is recognized as one of the most environmentally friendly methods for generating electricity, leading to a consistent increase in the production of silicon-based solar cells. However, the increasing use of solar cells means that there will be a significant amount of waste silicon-based solar cells. Thus, it has become increasingly important to develop technologies for recycling silicon waste from discarded solar cells. The primary objective of this study is to develop a process for recycling silicon waste from the photovoltaic industry. The process involves an acid-washing step to remove impurities and improve silicon purity, followed by ball milling to reduce the size and improve uniformity of the silicon waste particles. Finally, a mixture of conductive carbon and polymer binder is added to the silicon particles to produce an anode for a lithium-ion battery. This study aims to contribute to the sustainable utilization of waste silicon-based solar cells and the development of more environmentally friendly energy storage technologies.
Results/Contributions

We utilize silicon waste, which is recycled from the photovoltaic industry, as the raw material for the anode of a lithium-ion battery. However, the silicon waste contains impurities such as silicon dioxide, organic solvents, and metals that negatively impact the anode's quality. To address this issue, we use an acidic solution to purify the silicon waste and improve its purity. Despite purification, the silicon waste still has a large particle size and a tendency to agglomerate, which would hinder the preparation of the lithium-ion battery anode. Therefore, we subjected the silicon waste to ball-milling to homogenize and reduce its particle size.

Next, we mixed the processed silicon particles with conductive carbon and two different polymer binders. One binder was added to enhance the structural strength of the silicon anode and improve adhesion between the electrode and current collector. The other was added to increase the overall electrode structure's flexibility, which reduces the impact of silicon anode volume expansion on battery performance during lithiation/delithiation. Finally, we coated the mixture onto copper foil and dried it to prepare the anode of the lithium-ion battery.

Experimental results demonstrate that the lithium-ion battery made from recycled silicon waste maintains 80% of capacity retention after 100 cycles. This study's approach contributes to the sustainable utilization of silicon waste from the photovoltaic industry and the development of environmentally friendly energy storage technologies.

Keywords
Solar wasteRecyclingWaste siliconLithium-ion batteriesAnode