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 mitigated degradation. As its commercial adoption grows, yet no scalable recycling strategies currently exist for its manufacturing scrap. In this work, we report two water-based delamination methods: ice-stripping and ultrasound separation, for the direct recycling of Si/Gr electrodes. Ice stripping achieves a recovery efficiency of 98 ± 1%, preserving the structural and electrochemical properties of the material. Recycled 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 exhibits lower recovery (89%) 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 $·kg⁻¹, reducing cost by ~70% compared to ultrasound and other conventional multiwashing methods. The global warming potential is reduced by 50% (1.2 kg CO₂e·kg⁻¹) compared with 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.