Waste-Derived Onion-Like Carbon Nanoparticles/Recycled Silicon Composite for Sustainable High-Performance Lithium-Ion Batteries

Abstract

The sustainable fabrication of electrode materials using waste streams offers a promising pathway toward low-cost and environmentally sustainable lithium-ion batteries (LIBs). In this work, waste-derived silicon (WD-Si) recovered from end-of-life solar panels was used to fabricate a high-performance Si/C composite anode. Waste rubber-derived carbon nanoparticles (MWRC), synthesized through an energy-efficient microwave-assisted process, were incorporated as the carbon component. Mechanical milling was employed to reduce the particle size of WD-Si, resulting in a broad particle-size distribution with a significant submicron fraction after only 60 min of processing. Structural analyses confirmed that the milled Si retained high crystallinity while developing nanosized polycrystalline domains. Microwave-assisted carbonization of waste rubber generated onion-like carbon nanoparticles that were uniformly distributed along the rough surfaces and edges of the Si particles, forming a conductive and mechanically robust framework. The WD-Si/MWRC composite exhibited significantly improved electrochemical performance compared with bare WD-Si and commercial Si electrodes. The composite delivered initial discharge capacities of 2291.4, 1806.7, and 1280.1 mAh g⁻¹ at 0.1, 0.2, and 0.5 C, respectively. After 50 cycles, the composite retained a reversible capacity of 663.8 mAh g⁻¹, whereas commercial Si retained only 242.8 mAh g⁻¹ under the identical conditions.