98% Capacity After 2,000 Cycles: A Laser Technique for Better Lithium-Ion Anodes

Silicon anodes could store ten times more lithium than the graphite used in today's batteries. They also crack, swell, and die within a few hundred cycles — which is why they've been a promising future technology for two decades without breaking into the mainstream.

A team at Tel Aviv University thinks they've cleared the hardest remaining hurdle. In a paper published in Nano-Micro Letters, researchers Avinash Kothuru, Gil Daffan, and Fernando Patolsky describe a single-step laser process that simultaneously synthesizes and prelithiates silicon-graphene composite anodes under ambient conditions. The result: more than 98% capacity retention after 2,000 charge cycles, with near-zero performance decay in both half and full cells.

The core problem with silicon anodes is structural. When lithium ions flow in during charging, silicon expands by up to 300%. That expansion cracks the electrode, exposes fresh surface area, and triggers continuous solid electrolyte interphase (SEI) growth — the gummy layer that chokes battery performance. Most strategies address either the expansion (nanostructuring, composites) or the lithium loss (prelithiation). The Tel Aviv team does both in the same step.

Their process starts with a simple ternary blend: phenolic resin, silicon nanoparticles, and a common lithium salt — LiOH, Li2CO3, LiNO3, LiF, or LiClO4 all worked. A low-power laser scans the blend under regular air. The laser pulse generates localized temperatures above 2,000 Kelvin and pressures above 1 gigapascal, graphitizing the phenolic resin and triggering interfacial solid-state reactions between the silicon and lithium salt. The result is a self-standing composite: partially lithiated silicon nanoparticles with a thin lithium silicate shell — roughly 10 nanometers — embedded in a porous laser-induced graphene matrix.

No binders. No conductive additives. No exotic lithium precursors. No inert atmosphere required.

The performance numbers are what get attention: a specific capacity above 1,700 mAh per gram at room temperature, compared to roughly 370 mAh/g for graphite anodes in commercial cells. Initial coulombic efficiency exceeds 97%. At a fast cycling rate of 5 amps per gram, the anode retains more than 98% of its capacity after 2,000 cycles. After 4,500 cycles, it's still at 83%. The researchers validated the approach in full cells paired with lithium iron phosphate cathodes; those cells showed no measurable capacity degradation over 500 cycles at 1C rate.

Fast charging works too. The anode retains 63% of its maximum capacity at 10 amps per gram — a charging rate that would obliterate a conventional graphite cell.

The practical significance of prelithiation deserves some unpacking. When a battery first charges, lithium binds irreversibly to the anode surface, forming the SEI layer. That lithium is gone from the usable capacity. In silicon anodes, the problem is acute — the first-cycle lithium loss is severe enough that even a cell with theoretically high silicon content can end up with less usable energy than a graphite cell. Prelithiation pre-loads the anode with lithium before assembly, compensating for that first-cycle loss and stabilizing the SEI. The Tel Aviv approach does this chemically, in situ, without requiring metallic lithium or complicated dry-room processing.

Scalability is the question every battery researcher gets asked, and the team has a partial answer. They've demonstrated a 20-centimeter-long continuous fabrication, with clear potential for roll-to-roll integration. Fabrication rates exceed hundreds of square centimeters per hour. That's not yet a production figure, but it's a plausible manufacturing pathway — especially compared to conventional prelithiation approaches that require separate chemical or electrochemical steps.

The paper appears in Nano-Micro Letters, a Springer Nature journal, published January 26, 2026. The research was funded by Tel Aviv University's School of Chemistry and Department of Materials Science and Engineering.

What's worth watching: the gap between lab-scale cycling performance and commercially viable cell production is where most battery advances stall. The roll-to-roll pathway the team describes is the right direction, but electrode engineering at commercial scale introduces variables — coating uniformity, electrolyte wetting, calendar life — that a 20-centimeter demo doesn't answer. The fact that the process works in air and uses commodity precursors is genuinely unusual and makes the manufacturing story simpler than most prelithiation routes. Whether it survives contact with a real battery factory is the test that matters next.

The lithium silicate shell forming on the silicon particle surface — roughly 10 nanometers — is worth flagging for anyone tracking artificial SEI layer research. It's doing the same job as the coatings and additives that cell manufacturers spend considerable effort optimizing, but it forms intrinsically during the laser step. That may or may not translate to conventional cell manufacturing, but it's an interesting structural outcome.

Patolsky's group has been working on laser-induced graphene structures for battery applications for several years. Prior work includes graphene-silicon composites from phenolic precursors and phosphorus-graphene adducts. This paper represents a step-change in cycle life over earlier iterations, achieved by adding the lithium salt component that enables in-situ prelithiation.