A research team led by Professor Tae-Wook Kim of Jeonbuk National University (JBNU) (Graduate School of Flexible Pinted Electronics, Dept. of JBNU-KIST Industry-Academia Convergence Research) has developed a technology that can dramatically improve the performance of a triboelectric nanogenerator that converts everyday static electricity into electrical energy, attracting attention from the global academic community.

The team, together with Professor Seung-Ki Lee's research group from Pusan National University (Department of Materials Science and Engineering), developed an innovative device architecture that maximizes generation efficiency by exploiting the porous structure of a copper nanosheet film (Cu Nanosheet Film).

The study lists PhD candidate Dae-hong Kim (Graduate School of Flexible Pinted Electronics) as first author, and was published in the latest issue of Advanced Materials (IF = 26.8, top 2.3% in JCR). It is significant in that it presents a new paradigm for applying nanomaterials to energy-harvesting devices.

The single-crystal copper nanosheets developed by Professor Kim's team have a two-dimensional structure with a very high aspect ratio. When fabricated into films, they form a hierarchical porous structure in which roughly 66% of the interior is void. The researchers coated these voids with a solution of the silicone polymer PDMS (Polydimethylsiloxane), filling the film's micro-voids and thereby dramatically expanding the contact area between the electrode and the dielectric.

Applied to a triboelectric nanogenerator, this unique architecture produced an electrode–dielectric–electrode structure in which the copper nanosheet electrode and PDMS dielectric act as micro-capacitors inside the dielectric, substantially increasing capacitance.

As a result, the device achieved a power density about 590% higher than conventional copper thin-film-based generators and demonstrated excellent durability with no output degradation after more than 100,000 repeated operations. This represents the highest stability reported among similar studies to date.

Moreover, the device maintained electromagnetic interference shielding (EMI SE) performance above 30 dB after over 5,000 repeated operations, and exhibited a high-efficiency heating characteristic that reached 59.4°C at a low voltage of 5 V. In other words, it was developed into a multifunctional self-powering platform capable of simultaneous energy harvesting, EMI shielding, and flexible heating within a single structure.

Professor Tae-Wook Kim stated, "This study is the first case of realizing a high-performance, multifunctional self-powering device using a single material combination and a simple solution process. It will serve as a foundational technology that can be extended to various applications such as wearable electronics, self-powered sensors, flexible heating modules, and electromagnetic shielding."

The research was supported by the Ministry of Science and ICT and the National Research Foundation of Korea. The work was carried out jointly by Professor Tae-Wook Kim (JBNU, corresponding author), Professor Seung-Ki Lee (Pusan National University, corresponding author), Dr. Su-Gang Bae of the Korea Institute of Science and Technology (KIST), and Professor Joo-Hyuk Lee's research team from the Daegu Gyeongbuk Institute of Science and Technology (DGIST).