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Compiled by Bao Hien

South Korean scientists have applied semiconductor fabrication techniques to create nanotube structures on copper foil, helping lithium deposit more uniformly and suppressing the formation of dendrites that can damage batteries. The technology offers a potential pathway to developing anode-free batteries with higher energy density without adding extra material weight.

The research was led by Professor Jinwoo Lee and Professor Hee-Tae Jung of the Department of Chemical and Biomolecular Engineering at the Korea Advanced Institute of Science and Technology (KAIST), in collaboration with Kyungpook National University and the National NanoFab Center. The findings were published online in Advanced Functional Materials on September 1, 2026, and announced by KAIST on September 22.

Creating Nanostructures on Copper Foil Using Semiconductor Technology

Unlike conventional lithium-ion batteries, which use graphite as the anode material to store lithium ions, anode-free batteries eliminate this layer entirely. During charging, lithium from the cathode moves across the cell and deposits directly onto the copper foil, which serves only as a current collector.

This design reduces the amount of material required, creating opportunities to increase energy density per unit of weight and volume. According to an earlier study by Professor Lee's team, anode-free batteries could achieve energy densities 30–50% higher than conventional lithium-ion batteries while also simplifying manufacturing processes.

However, controlling lithium deposition remains a major challenge. On a flat copper surface, lithium tends to accumulate at certain locations, gradually forming needle-like structures known as dendrites. These structures not only accelerate capacity degradation over repeated charge-discharge cycles but can also penetrate the separator and cause short circuits.
Previous approaches have mainly involved adding excess lithium or applying protective coatings to the electrodes. Although these methods can improve stability, they also increase battery weight and volume, partially offsetting the advantages of the anode-free design.

To address this problem, the KAIST team turned to semiconductor fabrication techniques to redesign the surface structure of the copper foil.

Using a technique known as secondary sputtering lithography, the researchers created an evenly arranged array of microscopic tubes on the copper surface. Each tube measures approximately 300 nm in diameter and 150 nm in height. This structure increases the available surface area by about four times compared with flat copper foil, providing more sites for lithium deposition and reducing the tendency for lithium to accumulate at individual points.

A Nanoscale Coating to Control Chemical Reactions

In addition to redesigning the surface, the researchers applied an approximately 10-nm-thick coating of MXene, a two-dimensional material, over the nanotube structures.

The MXene layer acts as an intermediate coating that regulates reactions at the electrode surface. When exposed to an electrolyte containing LiPF6 salt, the material promotes the formation of a lithium fluoride (LiF)-rich protective layer. This layer helps suppress unwanted reactions between lithium and the electrolyte while controlling dendrite growth.

Advanced analytical techniques, including X-ray photoelectron spectroscopy, time-of-flight secondary ion mass spectrometry and transmission electron microscopy, confirmed that the protective layer formed uniformly across the MXene surface.

According to Professor Jinwoo Lee, the study demonstrates that precision fabrication techniques originally developed for the semiconductor industry can be used to control lithium deposition sites while simultaneously creating a stable protective layer for electrodes.

He described the approach as a promising way to extend battery lifespan without significantly increasing material weight or volume.

A Consistent Focus on Electrode Surface Engineering

The latest study builds on Professor Lee's team's broader research into controlling reactions at electrode surfaces. In December 2025, the group published a study in Joule introducing a method for coating electrodes with an approximately 15-nm-thick artificial polymer layer using chemical vapor deposition.

Both studies focus on modifying electrode surfaces rather than changing electrolyte composition or adding excess lithium. According to the researchers, this approach could facilitate integration into existing battery manufacturing processes. The earlier polymer-coating method was also considered potentially compatible with continuous roll-to-roll production lines.

The use of semiconductor fabrication techniques to precisely engineer materials at the nanoscale points to a new direction in the development of next-generation batteries. Rather than increasing the amount of material to improve stability, researchers are seeking to enhance performance through precise control of surface structures and electrochemical reactions.

Further Data Needed Before Commercialization

Despite its potential, the technology requires further evaluation in terms of performance and large-scale manufacturing. Currently available announcements do not provide comprehensive data on charge-discharge cycle life, capacity retention or the actual energy density of the experimental batteries. These figures are necessary to determine how much improvement the technology offers over conventional designs.

Manufacturing costs are another concern. Lithography offers high precision but typically requires sophisticated equipment and complex processing. Meanwhile, copper foil used in electric vehicle batteries must be manufactured over large areas at low cost. Maintaining uniform nanoscale structures across such surfaces remains a challenge that needs to be verified.

The technology has also yet to be tested in actual electric vehicles. Its commercial viability will therefore depend on further assessments of durability, manufacturing costs and the ability to scale up production in subsequent development stages.