Researchers at Israel's Tel Aviv University recently demonstrated a single-step laser process that simultaneously fabricates and prelithiates silicon-graphene anodes under ambient conditions, delivering virtually zero capacity decay over thousands of high‑rate cycles. The method directly addresses two key problems of silicon anodes - large volume changes and first‑cycle lithium loss - without relying on reactive lithium metal, moisture‑sensitive reagents, or multi‑step ex situ prelithiation.
a Schematic overview of the single-step, ambient, and low-power laser irradiation process applied to a blend of Li salt, phenolic resin, and SiNPs for the synthesis of self-standing, porous, prelithiated PL-SiNP/LIG composite anodes. b Molecular-scale schematic with the proposed laser irradiation mechanism of the ternary blend, inducing LIG formation while concomitantly triggers in situ prelithiation and encapsulation of SiNPs. c Demonstration of prelithiated SiNP/LIG anode synthesis with large-area sheet formation, highlighting the scalability of the process. Image from: Nano-Micro Letters
The process starts from a ternary blend of phenolic resin, silicon nanoparticles (SiNPs), and a common lithium salt such as LiOH, Li₂CO₃, LiNO₃, LiF, or LiClO₄. Low‑power laser irradiation under ambient atmosphere generates localized temperatures above 2000 K and pressures exceeding 1 GPa, converting the resin into a porous, conductive laser‑induced graphene (LIG) matrix while driving solid‑state reactions that prelithiate the silicon surface and form stable interfacial phases. The result is a self‑standing, additive‑free SiNP/LIG film in which each nanoparticle retains a crystalline Si core for high capacity, wrapped by a ~10 nm lithium silicate shell that compensates first‑cycle lithium losses and chemically anchors the particles to the graphene scaffold.
Advanced characterization (EELS, TOF‑SIMS, XPS, XRD) reveals uniform lithium distribution and robust Li–Si–O–C bonding, confirming that prelithiation and matrix formation occur uniformly throughout the composite. Electrochemically, the prelithiated anodes show lithium‑ion diffusion coefficients up to
3.6×10−11 cm² s⁻¹, charge‑transfer resistance below 20 Ω, and an initial coulombic efficiency above 97%, far surpassing non‑prelithiated analogues. At 5 A g⁻¹ they deliver >1700 mAh g⁻¹ with >98% capacity retention over 2000 cycles (capacity decay <2%), and still retain about 83% capacity after 4500 cycles; at 10 A g⁻¹ they maintain up to 63% of their maximum capacity, highlighting strong fast‑charging capability.
The approach is broadly compatible with common lithium salts, with LiOH giving the best performance, likely due to alkaline‑promoted densification and improved contact between silicon and the lithium source during laser processing. Full cells pairing these prelithiated anodes with LiFePO₄ cathodes show no measurable capacity loss over 500 cycles at 1C, and the team demonstrates fabrication of self‑standing strips up to 20 cm long with processing rates of hundreds of cm² per hour, suggesting straightforward integration with roll‑to‑roll manufacturing. Collectively, this laser‑driven, ambient, in situ prelithiation route offers a practical path to high‑capacity, long‑life silicon anodes for next‑generation lithium‑ion batteries.
