Lithium metal is considered one of the most promising anode materials for next-generation batteries because of its exceptionally high theoretical capacity and low electrochemical potential. However, conventional lithium metal batteries often rely on relatively thick lithium foils, which increase battery weight and limit energy density. Using thinner lithium anodes could significantly improve battery performance, but producing them reliably remains difficult. In addition, ultrathin anodes contain less available lithium, making them more sensitive to lithium loss during repeated charging and discharging.
One major manufacturing challenge is the poor wettability of molten lithium on copper current collectors. Instead of spreading evenly, molten lithium tends to form droplets, making it difficult to produce uniform, continuous ultrathin films. Conventional fabrication methods can also require expensive equipment or complex processing steps.
To address this issue, the researchers developed a mask-assisted screen-printing method that takes a different approach. Rather than forcing molten lithium to cover the entire copper surface, they printed it through a patterned mask to form regularly arranged, isolated lithium microdiscs. By adjusting the size, spacing, and thickness of these microdiscs, the researchers could precisely control the amount of lithium deposited on the electrode.
This approach enabled the fabrication of lithium arrays with equivalent thicknesses of 10, 20, and 28 μm. The team also demonstrated large-area production of approximately 30 × 10 cm². Importantly, the spaces between the lithium microdiscs help accommodate volume changes during battery operation and reduce mechanical stress, improving the structural stability of the anode.
Beyond improving fabrication, the researchers introduced magnesium bis(trifluoromethanesulfonyl)imide, Mg(TFSI)₂, into molten lithium to enhance the stability of the electrode interface. During processing, Mg(TFSI)₂ reacts with lithium to generate inorganic compounds, including LiF, Li₃N, and Li₂S, as well as lithium–magnesium alloys.
These components help guide more uniform lithium deposition and promote the formation of a stable, inorganic-rich solid electrolyte interphase (SEI). This protective interphase reduces unwanted reactions between lithium and the electrolyte, while the inorganic particles provide favorable sites for lithium deposition. Together with the patterned array structure, these effects suppress irregular lithium growth and reduce the loss of active lithium during cycling.
The benefits were demonstrated in lithium metal batteries using several high-loading cathode materials. In liquid-electrolyte cells, an anode with an equivalent lithium thickness of 10 μm, paired with a lithium iron phosphate (LFP) cathode, maintained stable performance for more than 260 cycles with a Coulombic efficiency above 99.8%. In comparison, the corresponding unmodified lithium array showed much faster capacity degradation.
The researchers also evaluated the anodes with high-loading nickel-rich cathodes. Based on stack-level energy-density calculations, batteries using a 20 μm-equivalent lithium anode achieved a gravimetric energy density of 504 Wh kg⁻¹ and a volumetric energy density of 1071 Wh L⁻¹. These results demonstrate the potential of ultrathin lithium arrays to reduce unnecessary lithium mass while maintaining high energy-storage performance.
The advantages of the lithium array design also extended to solid-state battery systems. Using an in situ polymerized gel electrolyte, the researchers demonstrated improved cycling performance with high-loading cathodes. The spaces between the lithium microdiscs help accommodate volume changes, while the reinforced interface promotes more stable contact between the anode and electrolyte. These complementary effects support more uniform lithium deposition and improved cycling reliability across different electrolyte systems.
This study presents a practical strategy for addressing two major challenges of ultrathin lithium metal anodes: difficult fabrication and unstable cycling. By combining screen-printed lithium arrays with inorganic-rich interface engineering, the researchers developed lightweight, structurally stable anodes suitable for both liquid- and solid-state batteries. The approach offers a promising direction for improving the energy density and cycling performance of future lithium metal batteries.
Title: Screen-Printed Li Arrays with Reinforced Interphase as Ultrathin Anodes for High-Energy–Density Liquid- and Solid-State Batteries
Journal Name: Nano-Micro Letters
DOI: https://doi.org/10.1007/s40820-026-02342-1
URL: https://scholarcast.cast.org.cn/news/2116063013841973248
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Nano-Micro Letters
Screen-Printed Li Arrays with Reinforced Interphase as Ultrathin Anodes for High-Energy–Density Liquid- and Solid-State Batteries
21-Aug-2026