Sustainable direct recycling of Si/Gr scrap electrodes using water-based methods: a green and scalable delamination approach

Abstract

Silicon–graphite (Si/Gr) composites are emerging as alternative anode materials for lithium-ion batteries because they combine higher energy density with improved storage capacity. As its commercial adoption grows, it is fundamental to develop recycling strategies for the currently most available source of this type of material, the manufacturing scrap. In this pioneering work, we report two water-based, delamination methods: ice-stripping and ultrasound delamination, for the direct recycling of Si/Gr scrap electrodes. Ice-stripping achieves a recovery efficiency of 98 ± 1%, while preserving the material's structural and electrochemical properties. The electrodes retain 94% of the initial capacity (503 mAh g⁻¹) after 100 cycles, closely matching the performance of pristine electrodes. In contrast, ultrasound-assisted delamination shows lower recovery yield and capacity performance. A preliminary environmental and economic analysis highlights ice-stripping as the most cost-effective and sustainable recycling option, with a delamination cost of 1.08$ per kg, reducing cost by ∼70% compared to ultrasound and other conventional multiwashing methods. The global warming potential is reduced by 50% (1.2 kg CO₂e per kg) compared to the other delamination techniques, and is more than 30-fold lower than that associated with producing an electrode from pristine Si/Gr. These findings establish a low-impact, scalable pathway for Si/Gr recycling, supporting the development of circular battery manufacturing under upcoming regulatory and sustainability frameworks.