To develop batteries that last longer on a single charge, more energy must be stored within the same size and weight.
A research team led by Dr. San Moon and Dr. Jungdon Suk at the Korea Research Institute of Chemical Technology (KRICT, President Seokmin Shin) has developed a dry thick-film cathode technology by incorporating graphitic carbon nitride (g-C3N4) as a cathode additive for the first time. The additive enhances electrolyte wettability, allowing the electrolyte to penetrate the electrode more effectively, while reducing the energy required for lithium ions to migrate into the cathode active material. The research was conducted in collaboration with domestic universities, including Seoul National University and Yonsei University, as well as Thermo Fisher Scientific Korea, a global scientific instrumentation company.
Increasing the thickness of battery electrodes allows more active material, which stores electrical energy, to be incorporated while reducing the relative amount of current collectors and separators required. This approach is advantageous for producing high-energy-density batteries capable of storing more energy, including high-capacity batteries designed for long-range electric vehicles. However, as electrodes become thicker, lithium-ion transport into their deeper regions slows down, causing a phenomenon similar to a "lithium-ion traffic jam." Consequently, electrochemical reactions become concentrated near the electrode surface, making it difficult to fully utilize the energy stored within the electrode.
Conventional battery electrodes are widely manufactured using a wet process, in which cathode active materials, binders, and other components are mixed with a solvent, coated onto a current collector, and subsequently dried. As electrode thickness increases, however, the binder can migrate toward the electrode surface during drying, resulting in a nonuniform distribution of components within the electrode. Dry electrode manufacturing eliminates the need for solvents and drying steps, thereby mitigating these problems. Nevertheless, it has not fully resolved the increasing resistance to lithium-ion transport associated with thicker electrodes.
The research team addressed this challenge by using porous graphitic carbon nitride (g-C3N4) as a "lithium-ion guide" within the electrode. Nitrogen atoms on the surface of the g-C3N4 additive temporarily capture and release passing lithium ions through the formation of transient lithium–nitrogen (Li–N) bonds. Similar to placing intermediate transfer hubs inside a large building, this process helps lithium ions shed their surrounding electrolyte solvent molecules and enter the cathode active material more easily.
As a result, the activation energy required for lithium-ion charge transfer decreased by 56%, from 49.8 to 22.1 kJ/mol. At the same time, the porous structure of g-C3N4 enhanced electrolyte wettability, promoting a more uniform distribution of lithium ions throughout the electrode.
The dry thick-film electrode, approximately 68 μm thick and containing 0.5 wt% g-C3N4, exhibited a 165.9% increase in discharge capacity at a high discharge rate of 3C, from 58.8 to 156.2 mAh/g. Its power density also increased by up to 2.85 times. In pouch-type full cells, capacity retention after 600 charge–discharge cycles improved from 72.9% in the additive-free electrode to 81.3% in the electrode containing g-C3N4.
However, the researchers found that adding more g-C3N4 does not necessarily lead to better performance. Because g-C3N4 has poor electrical conductivity, excessive amounts increase the electrode's electrical resistance. In addition, the spring-back effect, in which a compressed electrode partially expands over time, makes the internal ion-transport pathways more tortuous. The team therefore demonstrated that optimizing electrochemical performance requires the simultaneous design of the additive content, its positioning within the electrode, and the electrode's pore structure.
Dry electrode manufacturing has significant potential to reduce manufacturing costs, energy consumption, and production space by eliminating solvent-drying and recovery processes. However, the present study did not directly measure actual mass-production yields or reductions in manufacturing costs.
The research was published as a cover article in the August 2026 issue of the international scientific journal Exploration (Impact Factor: 30.4). Dr. San Moon and Dr. Jungdon Suk of KRICT served as corresponding authors, while Hye Ji Eun, a post-master's researcher, participated as the first author.
