Abstract

Device-level performance in MXenes is dictated by architecture—planar nanosheets are optimal for electromagnetic interference (EMI) shielding, while scrolled structures enhance ion transport for energy storage—particularly when morphology is programmed at synthesis. Whether such architectures can be deterministically encoded through precursor stoichiometry remains unresolved. Here, we demonstrate that precise carbon stoichiometry control in Ti3AlCxO2-x MAX phases tunes internal lattice strain and thereby directs the emergent MXene architecture. Carbon-rich precursors (x = 1.94) yield strain-relieved, high-crystalline nanosheets with metallic conductivity (∼23 300 S cm−1), enabling ultrathin films with record-high EMI shielding performances across 8 µm) and robust W-band retention after 5,000 bending cycles (r = 2.5 mm). In contrast, carbon-deficient precursors (x = 1.71) introduce lattice compression and oxygen substitution, triggering spontaneous scrolling upon delamination. The resulting nanoscrolls offer exceptional ion accessibility, achieving 657 F g−1 at 2 mV s−1 with 99.4% retention over 12 000 cycles. This stoichiometry-programmed approach establishes a synthesis-stage lever linking MAX chemistry to MXene architecture and function, enabling application-specific architecture design within established MAX/MXene synthesis and solution-processing workflows for next-generation electronics and energy storage. 

Researchers at UNIST have discovered a simple way to control MXene’s structure by adjusting the carbon content in its precursor. This breakthrough enables the creation of tailored MXene materials optimized for high-frequency electromagnetic interference (EMI) shielding and rapid energy storage.

MXene, a two-dimensional material composed of metal and carbon layers, is celebrated for its excellent electrical conductivity and adaptability. Its potential spans batteries, sensors, and flexible electronics.

With the rise of 6G technology and advanced radar systems, shielding devices against high-frequency interference has become critical. At the same time, the demand for quick, reliable energy storage continues to grow.

Led by Professor Soon-Yong Kwon from the Graduate School of Semiconductor Materials and Devices Engineering and Professor EunMi Choi from the Department of Electrical Engineering, the team showed that changing the carbon content in MAX precursors influences how MXene forms during synthesis.

This control method results in two distinctly different structures. When using carbon-rich precursors, the process yields flat, highly crystalline nanosheets that exhibit excellent electrical conductivity, effective electromagnetic shielding at 100 GHz, and maintain flexibility and durability under repeated bending. Conversely, employing carbon-deficient precursors induces the spontaneous formation of nanoscrolls, which significantly enhance ion transport. These nanoscroll structures enable high-capacity energy storage, achieving a capacitance of 657 F/g and a cycle life exceeding 12,000 cycles.

This work confirms that simple adjustments to precursor composition can produce MXene structures tailored for specific applications—flat sheets for shielding and scrolls for energy storage—within a streamlined process.

First author Jaeeun Park explains, “We showed that flat MXene sheets are ideal for electromagnetic shielding, while scroll structures are better suited for energy storage. By controlling the precursor, we can design the material for different functions without changing the synthesis method.”

Professor Kwon adds, “Last year, we enhanced MXene’s conductivity and broadband shielding through nitrogen doping. Now, we’ve demonstrated how to design the material’s shape from the start. The ultra-thin, flexible MXene performs well at 100 GHz and withstands bending, making it a promising lightweight, flexible shield for future 6G and radar systems.”

Supported by the Ministry of Science and ICT (MSIT) and the National Research Foundation of Korea (NRF), the study was published in Advanced Materials on May 18, 2026.

Journal Reference

Jaeeun Park, Ju-Hyoung Han, Yujin Chae, et al ., “Stoichiometry-Programmed MXenes via Precursor Engineering for High-Performance EMI Shielding and Energy Storage,” Adv. Mater ., (2026).