Eco-friendly silicon extraction from sand for enhanced anode materials in high-performance zinc-ion batteries

Ensuring access to efficient and sustainable energy storage is vital for supporting the growing use of renewable energy systems. Aqueous zinc-ion batteries (AZIBs) present a capable solution owed to their inherent safety and low-cost materials. However, their advancement is limited by zinc dendrite growth, restricted cycling performance, and moderate energy output. This work explores the integration of silicon nanoparticles (Si NPs) into zinc-based anodes as a strategy to overcome these barriers. We develop an eco-friendly process to extract Si NPs from nano sand using magnesium as a reducing agent at 800 °C under controlled conditions. These Si NPs are incorporated into a composite Zn/Si NP anode and assembled with a MnO₂ cathode and 2 M ZnSO₄ electrolyte to construct an AZIB cell. The Si NPs enhance surface stability, guide uniform zinc deposition, and suppress dendritic growth. Electrochemical testing confirms improved performance, with the Zn/Si NP anode achieving capacities of 298, 235, 214, and 199 mAh g⁻¹ at current densities of 0.25, 0.5, 1, and 2 A g⁻¹, respectively. The cell retains 83.6 % of its capacity after 115 cycles and maintains 99 % Coulombic efficiency, operating within a voltage range of 0.2–2 V. This study introduces a dual contribution: a low-energy route to recover silicon from abundant natural resources and its successful application in AZIBs. The result is a stable, high-capacity, and scalable battery design that supports the transition to more sustainable energy technologies.